ClickHouse/docs/en/sql-reference/functions/date-time-functions.md

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---
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slug: /en/sql-reference/functions/date-time-functions
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sidebar_position: 45
sidebar_label: Dates and Times
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---
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# Functions for Working with Dates and Times
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Most functions in this section accept an optional time zone argument, e.g. `Europe/Amsterdam`. In this case, the time zone is the specified one instead of the local (default) one.
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**Example**
CLICKHOUSE-2720: progress on website (#865) * update presentations * CLICKHOUSE-2936: redirect from clickhouse.yandex.ru and clickhouse.yandex.com * update submodule * lost files * CLICKHOUSE-2981: prefer sphinx docs over original reference * CLICKHOUSE-2981: docs styles more similar to main website + add flags to switch language links * update presentations * Less confusing directory structure (docs -> doc/reference/) * Minify sphinx docs too * Website release script: fail fast + pass docker hash on deploy * Do not underline links in docs * shorter * cleanup docker images * tune nginx config * CLICKHOUSE-3043: get rid of habrastorage links * Lost translation * CLICKHOUSE-2936: temporary client-side redirect * behaves weird in test * put redirect back * CLICKHOUSE-3047: copy docs txts to public too * move to proper file * remove old pages to avoid confusion * Remove reference redirect warning for now * Refresh README.md * Yellow buttons in docs * Use svg flags instead of unicode ones in docs * fix test website instance * Put flags to separate files * wrong flag * Copy Yandex.Metrica introduction from main page to docs * Yet another home page structure change, couple new blocks (CLICKHOUSE-3045) * Update Contacts section * CLICKHOUSE-2849: more detailed legal information * CLICKHOUSE-2978 preparation - split by files * More changes in Contacts block * Tune texts on index page * update presentations * One more benchmark * Add usage sections to index page, adapted from slides * Get the roadmap started, based on slides from last ClickHouse Meetup * CLICKHOUSE-2977: some rendering tuning * Get rid of excessive section in the end of getting started * Make headers linkable * CLICKHOUSE-2981: links to editing reference - https://github.com/yandex/ClickHouse/issues/849 * CLICKHOUSE-2981: fix mobile styles in docs * Ban crawling of duplicating docs * Open some external links in new tab * Ban old docs too * Lots of trivial fixes in english docs * Lots of trivial fixes in russian docs * Remove getting started copies in markdown * Add Yandex.Webmaster * Fix some sphinx warnings * More warnings fixed in english docs * More sphinx warnings fixed * Add code-block:: text * More code-block:: text * These headers look not that well * Better switch between documentation languages * merge use_case.rst into ya_metrika_task.rst * Edit the agg_functions.rst texts * Add lost empty lines
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``` sql
SELECT
toDateTime('2016-06-15 23:00:00') AS time,
toDate(time) AS date_local,
toDate(time, 'Asia/Yekaterinburg') AS date_yekat,
toString(time, 'US/Samoa') AS time_samoa
```
CLICKHOUSE-2720: progress on website and reference (#886) * update presentations * CLICKHOUSE-2936: redirect from clickhouse.yandex.ru and clickhouse.yandex.com * update submodule * lost files * CLICKHOUSE-2981: prefer sphinx docs over original reference * CLICKHOUSE-2981: docs styles more similar to main website + add flags to switch language links * update presentations * Less confusing directory structure (docs -> doc/reference/) * Minify sphinx docs too * Website release script: fail fast + pass docker hash on deploy * Do not underline links in docs * shorter * cleanup docker images * tune nginx config * CLICKHOUSE-3043: get rid of habrastorage links * Lost translation * CLICKHOUSE-2936: temporary client-side redirect * behaves weird in test * put redirect back * CLICKHOUSE-3047: copy docs txts to public too * move to proper file * remove old pages to avoid confusion * Remove reference redirect warning for now * Refresh README.md * Yellow buttons in docs * Use svg flags instead of unicode ones in docs * fix test website instance * Put flags to separate files * wrong flag * Copy Yandex.Metrica introduction from main page to docs * Yet another home page structure change, couple new blocks (CLICKHOUSE-3045) * Update Contacts section * CLICKHOUSE-2849: more detailed legal information * CLICKHOUSE-2978 preparation - split by files * More changes in Contacts block * Tune texts on index page * update presentations * One more benchmark * Add usage sections to index page, adapted from slides * Get the roadmap started, based on slides from last ClickHouse Meetup * CLICKHOUSE-2977: some rendering tuning * Get rid of excessive section in the end of getting started * Make headers linkable * CLICKHOUSE-2981: links to editing reference - https://github.com/yandex/ClickHouse/issues/849 * CLICKHOUSE-2981: fix mobile styles in docs * Ban crawling of duplicating docs * Open some external links in new tab * Ban old docs too * Lots of trivial fixes in english docs * Lots of trivial fixes in russian docs * Remove getting started copies in markdown * Add Yandex.Webmaster * Fix some sphinx warnings * More warnings fixed in english docs * More sphinx warnings fixed * Add code-block:: text * More code-block:: text * These headers look not that well * Better switch between documentation languages * merge use_case.rst into ya_metrika_task.rst * Edit the agg_functions.rst texts * Add lost empty lines * Lost blank lines * Add new logo sizes * update presentations * Next step in migrating to new documentation * Fix all warnings in en reference * Fix all warnings in ru reference * Re-arrange existing reference * Move operation tips to main reference * Fix typos noticed by milovidov@ * Get rid of zookeeper.md * Looks like duplicate of tutorial.html * Fix some mess with html tags in tutorial * No idea why nobody noticed this before, but it was completely not clear whet to get the data * Match code block styling between main and tutorial pages (in favor of the latter) * Get rid of some copypaste in tutorial * Normalize header styles * Move example_datasets to sphinx * Move presentations submodule to website * Move and update README.md * No point in duplicating articles from habrahabr here * Move development-related docs as is for now * doc/reference/ -> docs/ (to match the URL on website) * Adapt links to match the previous commit * Adapt development docs to rst (still lacks translation and strikethrough support) * clean on release * blacklist presentations in gulp * strikethrough support in sphinx * just copy development folder for now * fix weird introduction in style article * Style guide translation (WIP) * Finish style guide translation to English * gulp clean separately * Update year in LICENSE * Initial CONTRIBUTING.md * Fix remaining links to old docs in tutorial * Some tutorial fixes * Typo * Another typo * Update list of authors from yandex-team accoding to git log
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``` text
┌────────────────time─┬─date_local─┬─date_yekat─┬─time_samoa──────────┐
│ 2016-06-15 23:00:00 │ 2016-06-15 │ 2016-06-16 │ 2016-06-15 09:00:00 │
└─────────────────────┴────────────┴────────────┴─────────────────────┘
```
CLICKHOUSE-2720: progress on website (#865) * update presentations * CLICKHOUSE-2936: redirect from clickhouse.yandex.ru and clickhouse.yandex.com * update submodule * lost files * CLICKHOUSE-2981: prefer sphinx docs over original reference * CLICKHOUSE-2981: docs styles more similar to main website + add flags to switch language links * update presentations * Less confusing directory structure (docs -> doc/reference/) * Minify sphinx docs too * Website release script: fail fast + pass docker hash on deploy * Do not underline links in docs * shorter * cleanup docker images * tune nginx config * CLICKHOUSE-3043: get rid of habrastorage links * Lost translation * CLICKHOUSE-2936: temporary client-side redirect * behaves weird in test * put redirect back * CLICKHOUSE-3047: copy docs txts to public too * move to proper file * remove old pages to avoid confusion * Remove reference redirect warning for now * Refresh README.md * Yellow buttons in docs * Use svg flags instead of unicode ones in docs * fix test website instance * Put flags to separate files * wrong flag * Copy Yandex.Metrica introduction from main page to docs * Yet another home page structure change, couple new blocks (CLICKHOUSE-3045) * Update Contacts section * CLICKHOUSE-2849: more detailed legal information * CLICKHOUSE-2978 preparation - split by files * More changes in Contacts block * Tune texts on index page * update presentations * One more benchmark * Add usage sections to index page, adapted from slides * Get the roadmap started, based on slides from last ClickHouse Meetup * CLICKHOUSE-2977: some rendering tuning * Get rid of excessive section in the end of getting started * Make headers linkable * CLICKHOUSE-2981: links to editing reference - https://github.com/yandex/ClickHouse/issues/849 * CLICKHOUSE-2981: fix mobile styles in docs * Ban crawling of duplicating docs * Open some external links in new tab * Ban old docs too * Lots of trivial fixes in english docs * Lots of trivial fixes in russian docs * Remove getting started copies in markdown * Add Yandex.Webmaster * Fix some sphinx warnings * More warnings fixed in english docs * More sphinx warnings fixed * Add code-block:: text * More code-block:: text * These headers look not that well * Better switch between documentation languages * merge use_case.rst into ya_metrika_task.rst * Edit the agg_functions.rst texts * Add lost empty lines
2017-06-13 04:15:47 +00:00
## makeDate
Creates a [Date](../../sql-reference/data-types/date.md)
- from a year, month and day argument, or
- from a year and day of year argument.
**Syntax**
``` sql
makeDate(year, month, day);
makeDate(year, day_of_year);
```
Alias:
- `MAKEDATE(year, month, day);`
- `MAKEDATE(year, day_of_year);`
**Arguments**
- `year` — Year. [Integer](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md) or [Decimal](../../sql-reference/data-types/decimal.md).
- `month` — Month. [Integer](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md) or [Decimal](../../sql-reference/data-types/decimal.md).
- `day` — Day. [Integer](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md) or [Decimal](../../sql-reference/data-types/decimal.md).
- `day_of_year` — Day of the year. [Integer](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md) or [Decimal](../../sql-reference/data-types/decimal.md).
**Returned value**
- A date created from the arguments.
Type: [Date](../../sql-reference/data-types/date.md).
**Example**
Create a Date from a year, month and day:
``` sql
SELECT makeDate(2023, 2, 28) AS Date;
```
Result:
``` text
┌───────date─┐
│ 2023-02-28 │
└────────────┘
```
Create a Date from a year and day of year argument:
``` sql
SELECT makeDate(2023, 42) AS Date;
```
Result:
``` text
┌───────date─┐
│ 2023-02-11 │
└────────────┘
```
## makeDate32
Like [makeDate](#makeDate) but produces a [Date32](../../sql-reference/data-types/date32.md).
## makeDateTime
Creates a [DateTime](../../sql-reference/data-types/datetime.md) from a year, month, day, hour, minute and second argument.
**Syntax**
``` sql
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makeDateTime(year, month, day, hour, minute, second[, timezone])
```
**Arguments**
- `year` — Year. [Integer](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md) or [Decimal](../../sql-reference/data-types/decimal.md).
- `month` — Month. [Integer](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md) or [Decimal](../../sql-reference/data-types/decimal.md).
- `day` — Day. [Integer](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md) or [Decimal](../../sql-reference/data-types/decimal.md).
- `hour` — Hour. [Integer](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md) or [Decimal](../../sql-reference/data-types/decimal.md).
- `minute` — Minute. [Integer](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md) or [Decimal](../../sql-reference/data-types/decimal.md).
- `second` — Second. [Integer](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md) or [Decimal](../../sql-reference/data-types/decimal.md).
- `timezone` — [Timezone](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-timezone) for the returned value (optional).
**Returned value**
- A date with time created from the arguments.
Type: [DateTime](../../sql-reference/data-types/datetime.md).
**Example**
``` sql
SELECT makeDateTime(2023, 2, 28, 17, 12, 33) AS DateTime;
```
Result:
``` text
┌────────────DateTime─┐
│ 2023-02-28 17:12:33 │
└─────────────────────┘
```
## makeDateTime64
Like [makeDateTime](#makedatetime) but produces a [DateTime64](../../sql-reference/data-types/datetime64.md).
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**Syntax**
``` sql
makeDateTime64(year, month, day, hour, minute, second[, fraction[, precision[, timezone]]])
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```
## timestamp
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Converts the first argument 'expr' to type [DateTime64(6)](../../sql-reference/data-types/datetime64.md).
If a second argument 'expr_time' is provided, it adds the specified time to the converted value.
**Syntax**
``` sql
timestamp(expr[, expr_time])
```
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Alias: `TIMESTAMP`
**Arguments**
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- `expr` - Date or date with time. Type: [String](../../sql-reference/data-types/string.md).
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- `expr_time` - Optional parameter. Time to add. [String](../../sql-reference/data-types/string.md).
**Examples**
``` sql
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SELECT timestamp('2023-12-31') as ts;
```
Result:
``` text
┌─────────────────────────ts─┐
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│ 2023-12-31 00:00:00.000000 │
└────────────────────────────┘
```
``` sql
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SELECT timestamp('2023-12-31 12:00:00', '12:00:00.11') as ts;
```
Result:
``` text
┌─────────────────────────ts─┐
2023-09-27 20:24:31 +00:00
│ 2024-01-01 00:00:00.110000 │
└────────────────────────────┘
```
**Returned value**
- [DateTime64](../../sql-reference/data-types/datetime64.md)(6)
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## timeZone
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Returns the timezone of the current session, i.e. the value of setting [session_timezone](../../operations/settings/settings.md#session_timezone).
If the function is executed in the context of a distributed table, then it generates a normal column with values relevant to each shard, otherwise it produces a constant value.
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**Syntax**
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```sql
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timeZone()
```
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Alias: `timezone`.
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**Returned value**
- Timezone.
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Type: [String](../../sql-reference/data-types/string.md).
**Example**
```sql
SELECT timezone()
```
Result:
```response
┌─timezone()─────┐
│ America/Denver │
└────────────────┘
```
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**See also**
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- [serverTimeZone](#serverTimeZone)
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## serverTimeZone
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Returns the timezone of the server, i.e. the value of setting [timezone](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-timezone).
If the function is executed in the context of a distributed table, then it generates a normal column with values relevant to each shard. Otherwise, it produces a constant value.
**Syntax**
``` sql
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serverTimeZone()
```
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Alias: `serverTimezone`.
**Returned value**
- Timezone.
Type: [String](../../sql-reference/data-types/string.md).
**Example**
```sql
SELECT serverTimeZone()
```
Result:
```response
┌─serverTimeZone()─┐
│ UTC │
└──────────────────┘
```
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**See also**
- [timeZone](#timeZone)
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## toTimeZone
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Converts a date or date with time to the specified time zone. Does not change the internal value (number of unix seconds) of the data, only the value's time zone attribute and the value's string representation changes.
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**Syntax**
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``` sql
toTimezone(value, timezone)
```
Alias: `toTimezone`.
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**Arguments**
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- `value` — Time or date and time. [DateTime64](../../sql-reference/data-types/datetime64.md).
- `timezone` — Timezone for the returned value. [String](../../sql-reference/data-types/string.md). This argument is a constant, because `toTimezone` changes the timezone of a column (timezone is an attribute of `DateTime*` types).
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**Returned value**
- Date and time.
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Type: [DateTime](../../sql-reference/data-types/datetime.md).
**Example**
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```sql
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SELECT toDateTime('2019-01-01 00:00:00', 'UTC') AS time_utc,
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toTypeName(time_utc) AS type_utc,
toInt32(time_utc) AS int32utc,
toTimeZone(time_utc, 'Asia/Yekaterinburg') AS time_yekat,
toTypeName(time_yekat) AS type_yekat,
toInt32(time_yekat) AS int32yekat,
toTimeZone(time_utc, 'US/Samoa') AS time_samoa,
toTypeName(time_samoa) AS type_samoa,
toInt32(time_samoa) AS int32samoa
FORMAT Vertical;
```
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Result:
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```text
Row 1:
──────
time_utc: 2019-01-01 00:00:00
type_utc: DateTime('UTC')
int32utc: 1546300800
time_yekat: 2019-01-01 05:00:00
type_yekat: DateTime('Asia/Yekaterinburg')
int32yekat: 1546300800
time_samoa: 2018-12-31 13:00:00
type_samoa: DateTime('US/Samoa')
int32samoa: 1546300800
```
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**See Also**
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- [formatDateTime](#formatDateTime) - supports non-constant timezone.
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- [toString](type-conversion-functions.md#tostring) - supports non-constant timezone.
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## timeZoneOf
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Returns the timezone name of [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md) data types.
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**Syntax**
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``` sql
timeZoneOf(value)
```
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Alias: `timezoneOf`.
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**Arguments**
- `value` — Date and time. [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md).
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**Returned value**
- Timezone name.
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Type: [String](../../sql-reference/data-types/string.md).
**Example**
``` sql
SELECT timezoneOf(now());
```
Result:
``` text
┌─timezoneOf(now())─┐
│ Etc/UTC │
└───────────────────┘
```
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## timeZoneOffset
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Returns the timezone offset in seconds from [UTC](https://en.wikipedia.org/wiki/Coordinated_Universal_Time).
The function [daylight saving time](https://en.wikipedia.org/wiki/Daylight_saving_time) and historical timezone changes at the specified date and time into account.
The [IANA timezone database](https://www.iana.org/time-zones) is used to calculate the offset.
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**Syntax**
``` sql
timeZoneOffset(value)
```
Alias: `timezoneOffset`.
**Arguments**
- `value` — Date and time. [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md).
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**Returned value**
- Offset from UTC in seconds.
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Type: [Int32](../../sql-reference/data-types/int-uint.md).
**Example**
``` sql
SELECT toDateTime('2021-04-21 10:20:30', 'America/New_York') AS Time, toTypeName(Time) AS Type,
timeZoneOffset(Time) AS Offset_in_seconds, (Offset_in_seconds / 3600) AS Offset_in_hours;
```
Result:
``` text
┌────────────────Time─┬─Type─────────────────────────┬─Offset_in_seconds─┬─Offset_in_hours─┐
│ 2021-04-21 10:20:30 │ DateTime('America/New_York') │ -14400 │ -4 │
└─────────────────────┴──────────────────────────────┴───────────────────┴─────────────────┘
```
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## toYear
CLICKHOUSE-2720: progress on website (#865) * update presentations * CLICKHOUSE-2936: redirect from clickhouse.yandex.ru and clickhouse.yandex.com * update submodule * lost files * CLICKHOUSE-2981: prefer sphinx docs over original reference * CLICKHOUSE-2981: docs styles more similar to main website + add flags to switch language links * update presentations * Less confusing directory structure (docs -> doc/reference/) * Minify sphinx docs too * Website release script: fail fast + pass docker hash on deploy * Do not underline links in docs * shorter * cleanup docker images * tune nginx config * CLICKHOUSE-3043: get rid of habrastorage links * Lost translation * CLICKHOUSE-2936: temporary client-side redirect * behaves weird in test * put redirect back * CLICKHOUSE-3047: copy docs txts to public too * move to proper file * remove old pages to avoid confusion * Remove reference redirect warning for now * Refresh README.md * Yellow buttons in docs * Use svg flags instead of unicode ones in docs * fix test website instance * Put flags to separate files * wrong flag * Copy Yandex.Metrica introduction from main page to docs * Yet another home page structure change, couple new blocks (CLICKHOUSE-3045) * Update Contacts section * CLICKHOUSE-2849: more detailed legal information * CLICKHOUSE-2978 preparation - split by files * More changes in Contacts block * Tune texts on index page * update presentations * One more benchmark * Add usage sections to index page, adapted from slides * Get the roadmap started, based on slides from last ClickHouse Meetup * CLICKHOUSE-2977: some rendering tuning * Get rid of excessive section in the end of getting started * Make headers linkable * CLICKHOUSE-2981: links to editing reference - https://github.com/yandex/ClickHouse/issues/849 * CLICKHOUSE-2981: fix mobile styles in docs * Ban crawling of duplicating docs * Open some external links in new tab * Ban old docs too * Lots of trivial fixes in english docs * Lots of trivial fixes in russian docs * Remove getting started copies in markdown * Add Yandex.Webmaster * Fix some sphinx warnings * More warnings fixed in english docs * More sphinx warnings fixed * Add code-block:: text * More code-block:: text * These headers look not that well * Better switch between documentation languages * merge use_case.rst into ya_metrika_task.rst * Edit the agg_functions.rst texts * Add lost empty lines
2017-06-13 04:15:47 +00:00
Converts a date or date with time to the year number (AD) as `UInt16` value.
**Syntax**
```sql
toYear(value)
```
Alias: `YEAR`
**Arguments**
- `value` - a [Date](../data-types/date.md), [Date32](../data-types/date32.md), [DateTime](../data-types/datetime.md) or [DateTime64](../data-types/datetime64.md)
**Returned value**
- The year of the given date/time
Type: `UInt16`
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**Example**
```sql
SELECT toYear(toDateTime('2023-04-21 10:20:30'))
```
Result:
```response
┌─toYear(toDateTime('2023-04-21 10:20:30'))─┐
│ 2023 │
└───────────────────────────────────────────┘
```
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## toQuarter
Converts a date or date with time to the quarter number (1-4) as `UInt8` value.
**Syntax**
```sql
toQuarter(value)
```
Alias: `QUARTER`
**Arguments**
- `value` - a [Date](../data-types/date.md), [Date32](../data-types/date32.md), [DateTime](../data-types/datetime.md) or [DateTime64](../data-types/datetime64.md)
**Returned value**
- The quarter of the year (1, 2, 3 or 4) of the given date/time
Type: `UInt8`
**Example**
```sql
SELECT toQuarter(toDateTime('2023-04-21 10:20:30'))
```
Result:
```response
┌─toQuarter(toDateTime('2023-04-21 10:20:30'))─┐
│ 2 │
└──────────────────────────────────────────────┘
```
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## toMonth
Converts a date or date with time to the month number (1-12) as `UInt8` value.
**Syntax**
```sql
toMonth(value)
```
Alias: `MONTH`
**Arguments**
- `value` - a [Date](../data-types/date.md), [Date32](../data-types/date32.md), [DateTime](../data-types/datetime.md) or [DateTime64](../data-types/datetime64.md)
**Returned value**
- The month of the year (1 - 12) of the given date/time
Type: `UInt8`
**Example**
```sql
SELECT toMonth(toDateTime('2023-04-21 10:20:30'))
```
Result:
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```response
┌─toMonth(toDateTime('2023-04-21 10:20:30'))─┐
│ 4 │
└────────────────────────────────────────────┘
```
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## toDayOfYear
Converts a date or date with time to the number of the day of the year (1-366) as `UInt16` value.
**Syntax**
```sql
toDayOfYear(value)
```
Alias: `DAYOFYEAR`
**Arguments**
- `value` - a [Date](../data-types/date.md), [Date32](../data-types/date32.md), [DateTime](../data-types/datetime.md) or [DateTime64](../data-types/datetime64.md)
**Returned value**
- The day of the year (1 - 366) of the given date/time
Type: `UInt16`
**Example**
```sql
SELECT toDayOfYear(toDateTime('2023-04-21 10:20:30'))
```
Result:
```response
┌─toDayOfYear(toDateTime('2023-04-21 10:20:30'))─┐
│ 111 │
└────────────────────────────────────────────────┘
```
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## toDayOfMonth
Converts a date or date with time to the number of the day in the month (1-31) as `UInt8` value.
**Syntax**
```sql
toDayOfMonth(value)
```
Aliases: `DAYOFMONTH`, `DAY`
**Arguments**
- `value` - a [Date](../data-types/date.md), [Date32](../data-types/date32.md), [DateTime](../data-types/datetime.md) or [DateTime64](../data-types/datetime64.md)
**Returned value**
- The day of the month (1 - 31) of the given date/time
Type: `UInt8`
**Example**
```sql
SELECT toDayOfMonth(toDateTime('2023-04-21 10:20:30'))
```
Result:
```response
┌─toDayOfMonth(toDateTime('2023-04-21 10:20:30'))─┐
│ 21 │
└─────────────────────────────────────────────────┘
```
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## toDayOfWeek
2017-04-03 19:49:50 +00:00
Converts a date or date with time to the number of the day in the week as `UInt8` value.
2023-01-13 14:01:13 +00:00
The two-argument form of `toDayOfWeek()` enables you to specify whether the week starts on Monday or Sunday, and whether the return value should be in the range from 0 to 6 or 1 to 7. If the mode argument is omitted, the default mode is 0. The time zone of the date can be specified as the third argument.
| Mode | First day of week | Range |
|------|-------------------|------------------------------------------------|
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| 0 | Monday | 1-7: Monday = 1, Tuesday = 2, ..., Sunday = 7 |
| 1 | Monday | 0-6: Monday = 0, Tuesday = 1, ..., Sunday = 6 |
| 2 | Sunday | 0-6: Sunday = 0, Monday = 1, ..., Saturday = 6 |
| 3 | Sunday | 1-7: Sunday = 1, Monday = 2, ..., Saturday = 7 |
2017-04-03 19:49:50 +00:00
2023-01-13 14:01:13 +00:00
**Syntax**
``` sql
toDayOfWeek(t[, mode[, timezone]])
```
Alias: `DAYOFWEEK`.
**Arguments**
- `t` - a [Date](../data-types/date.md), [Date32](../data-types/date32.md), [DateTime](../data-types/datetime.md) or [DateTime64](../data-types/datetime64.md)
- `mode` - determines what the first day of the week is. Possible values are 0, 1, 2 or 3. See the table above for the differences.
- `timezone` - optional parameter, it behaves like any other conversion function
The first argument can also be specified as [String](../data-types/string.md) in a format supported by [parseDateTime64BestEffort()](type-conversion-functions.md#parsedatetime64besteffort). Support for string arguments exists only for reasons of compatibility with MySQL which is expected by certain 3rd party tools. As string argument support may in future be made dependent on new MySQL-compatibility settings and because string parsing is generally slow, it is recommended to not use it.
**Returned value**
- The day of the week (1-7), depending on the chosen mode, of the given date/time
**Example**
The following date is April 21, 2023, which was a Friday:
```sql
SELECT
toDayOfWeek(toDateTime('2023-04-21')),
toDayOfWeek(toDateTime('2023-04-21'), 1)
```
Result:
```response
┌─toDayOfWeek(toDateTime('2023-04-21'))─┬─toDayOfWeek(toDateTime('2023-04-21'), 1)─┐
│ 5 │ 4 │
└───────────────────────────────────────┴──────────────────────────────────────────┘
```
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## toHour
Converts a date with time to the number of the hour in 24-hour time (0-23) as `UInt8` value.
Assumes that if clocks are moved ahead, it is by one hour and occurs at 2 a.m., and if clocks are moved back, it is by one hour and occurs at 3 a.m. (which is not always exactly when it occurs - it depends on the timezone).
**Syntax**
```sql
toHour(value)
```
Alias: `HOUR`
**Arguments**
- `value` - a [Date](../data-types/date.md), [Date32](../data-types/date32.md), [DateTime](../data-types/datetime.md) or [DateTime64](../data-types/datetime64.md)
**Returned value**
- The hour of the day (0 - 23) of the given date/time
Type: `UInt8`
**Example**
```sql
SELECT toHour(toDateTime('2023-04-21 10:20:30'))
```
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Result:
```response
┌─toHour(toDateTime('2023-04-21 10:20:30'))─┐
│ 10 │
└───────────────────────────────────────────┘
```
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## toMinute
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Converts a date with time to the number of the minute of the hour (0-59) as `UInt8` value.
**Syntax**
```sql
toMinute(value)
```
Alias: `MINUTE`
**Arguments**
- `value` - a [Date](../data-types/date.md), [Date32](../data-types/date32.md), [DateTime](../data-types/datetime.md) or [DateTime64](../data-types/datetime64.md)
**Returned value**
- The minute of the hour (0 - 59) of the given date/time
Type: `UInt8`
2017-04-03 19:49:50 +00:00
**Example**
```sql
SELECT toMinute(toDateTime('2023-04-21 10:20:30'))
```
Result:
```response
┌─toMinute(toDateTime('2023-04-21 10:20:30'))─┐
│ 20 │
└─────────────────────────────────────────────┘
```
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## toSecond
Converts a date with time to the second in the minute (0-59) as `UInt8` value. Leap seconds are not considered.
**Syntax**
```sql
toSecond(value)
```
Alias: `SECOND`
**Arguments**
- `value` - a [Date](../data-types/date.md), [Date32](../data-types/date32.md), [DateTime](../data-types/datetime.md) or [DateTime64](../data-types/datetime64.md)
**Returned value**
- The second in the minute (0 - 59) of the given date/time
Type: `UInt8`
**Example**
```sql
SELECT toSecond(toDateTime('2023-04-21 10:20:30'))
```
Result:
2017-04-26 19:16:38 +00:00
```response
┌─toSecond(toDateTime('2023-04-21 10:20:30'))─┐
│ 30 │
└─────────────────────────────────────────────┘
```
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## toMilliSecond
Similar to the `toSecond` function, it converts a date with time to the milliseconds in the minute of the time as `UInt16` value.
**Syntax**
```sql
toMilliSecond(value)
```
*Arguments**
- `value` - a [Date](../data-types/date.md), [Date32](../data-types/date32.md), [DateTime](../data-types/datetime.md) or [DateTime64](../data-types/datetime64.md)
Alias: `MILLISECOND`
```sql
SELECT toMilliSecond(toDateTime('2023-04-21 10:20:30'))
```
Result:
```response
┌─toSecond(toDateTime('2023-04-21 10:20:30'))─┐
│ 30000 │
└─────────────────────────────────────────────┘
```
**Returned value**
- The millisecond in the minute (0 - 59) of the given date/time
Type: `UInt16`
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## toUnixTimestamp
Converts a string, a date or a date with time to the [Unix Timestamp](https://en.wikipedia.org/wiki/Unix_time) in `UInt32` representation.
2023-04-20 10:18:46 +00:00
If the function is called with a string, it accepts an optional timezone argument.
2020-03-20 10:10:48 +00:00
**Syntax**
2019-10-23 11:28:08 +00:00
2020-03-20 10:10:48 +00:00
``` sql
toUnixTimestamp(date)
2020-02-02 21:20:56 +00:00
toUnixTimestamp(str, [timezone])
```
**Returned value**
- Returns the unix timestamp.
Type: `UInt32`.
**Example**
2020-03-20 10:10:48 +00:00
``` sql
SELECT
'2017-11-05 08:07:47' AS dt_str,
toUnixTimestamp(dt_str) AS from_str,
toUnixTimestamp(dt_str, 'Asia/Tokyo') AS from_str_tokyo,
toUnixTimestamp(toDateTime(dt_str)) AS from_datetime,
toUnixTimestamp(toDateTime64(dt_str, 0)) AS from_datetime64,
toUnixTimestamp(toDate(dt_str)) AS from_date,
toUnixTimestamp(toDate32(dt_str)) AS from_date32
FORMAT Vertical;
```
Result:
2020-03-20 10:10:48 +00:00
``` text
Row 1:
──────
dt_str: 2017-11-05 08:07:47
from_str: 1509869267
from_str_tokyo: 1509836867
from_datetime: 1509869267
from_datetime64: 1509869267
from_date: 1509840000
from_date32: 1509840000
```
:::note
The return type of `toStartOf*`, `toLastDayOf*`, `toMonday`, `timeSlot` functions described below is determined by the configuration parameter [enable_extended_results_for_datetime_functions](../../operations/settings/settings.md#enable-extended-results-for-datetime-functions) which is `0` by default.
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Behavior for
* `enable_extended_results_for_datetime_functions = 0`:
* Functions `toStartOfYear`, `toStartOfISOYear`, `toStartOfQuarter`, `toStartOfMonth`, `toStartOfWeek`, `toLastDayOfWeek`, `toLastDayOfMonth`, `toMonday` return `Date` or `DateTime`.
* Functions `toStartOfDay`, `toStartOfHour`, `toStartOfFifteenMinutes`, `toStartOfTenMinutes`, `toStartOfFiveMinutes`, `toStartOfMinute`, `timeSlot` return `DateTime`. Though these functions can take values of the extended types `Date32` and `DateTime64` as an argument, passing them a time outside the normal range (year 1970 to 2149 for `Date` / 2106 for `DateTime`) will produce wrong results.
* `enable_extended_results_for_datetime_functions = 1`:
* Functions `toStartOfYear`, `toStartOfISOYear`, `toStartOfQuarter`, `toStartOfMonth`, `toStartOfWeek`, `toLastDayOfWeek`, `toLastDayOfMonth`, `toMonday` return `Date` or `DateTime` if their argument is a `Date` or `DateTime`, and they return `Date32` or `DateTime64` if their argument is a `Date32` or `DateTime64`.
* Functions `toStartOfDay`, `toStartOfHour`, `toStartOfFifteenMinutes`, `toStartOfTenMinutes`, `toStartOfFiveMinutes`, `toStartOfMinute`, `timeSlot` return `DateTime` if their argument is a `Date` or `DateTime`, and they return `DateTime64` if their argument is a `Date32` or `DateTime64`.
:::
2021-04-09 15:37:14 +00:00
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## toStartOfYear
2017-04-03 19:49:50 +00:00
Rounds down a date or date with time to the first day of the year. Returns the date as a `Date` object.
**Syntax**
```sql
toStartOfYear(value)
```
**Arguments**
- `value` - a [Date](../data-types/date.md), [Date32](../data-types/date32.md), [DateTime](../data-types/datetime.md) or [DateTime64](../data-types/datetime64.md)
2017-04-03 19:49:50 +00:00
**Returned value**
- The first day of the year of the input date/time
2023-01-05 16:37:05 +00:00
Type: `Date`
2023-01-05 16:37:05 +00:00
**Example**
2023-01-05 16:37:05 +00:00
```sql
SELECT toStartOfYear(toDateTime('2023-04-21 10:20:30'))
```
Result:
```response
┌─toStartOfYear(toDateTime('2023-04-21 10:20:30'))─┐
│ 2023-01-01 │
└──────────────────────────────────────────────────┘
```
## toStartOfISOYear
Rounds down a date or date with time to the first day of the ISO year, which can be different than a "regular" year. (See [https://en.wikipedia.org/wiki/ISO_week_date](https://en.wikipedia.org/wiki/ISO_week_date).)
2023-01-13 14:01:13 +00:00
**Syntax**
```sql
toStartOfISOYear(value)
2023-01-13 14:01:13 +00:00
```
**Arguments**
- `value` - a [Date](../data-types/date.md), [Date32](../data-types/date32.md), [DateTime](../data-types/datetime.md) or [DateTime64](../data-types/datetime64.md)
**Returned value**
- The first day of the year of the input date/time
Type: `Date`
2017-04-03 19:49:50 +00:00
**Example**
```sql
SELECT toStartOfISOYear(toDateTime('2023-04-21 10:20:30'))
```
Result:
2017-04-03 19:49:50 +00:00
```response
┌─toStartOfISOYear(toDateTime('2023-04-21 10:20:30'))─┐
│ 2023-01-02 │
└─────────────────────────────────────────────────────┘
```
## toStartOfQuarter
Rounds down a date or date with time to the first day of the quarter. The first day of the quarter is either 1 January, 1 April, 1 July, or 1 October.
Returns the date.
**Syntax**
```sql
toStartOfQuarter(value)
```
**Arguments**
- `value` - a [Date](../data-types/date.md), [Date32](../data-types/date32.md), [DateTime](../data-types/datetime.md) or [DateTime64](../data-types/datetime64.md)
**Returned value**
- The first day of the quarter of the given date/time
Type: `Date`
**Example**
```sql
SELECT toStartOfQuarter(toDateTime('2023-04-21 10:20:30'))
```
Result:
```response
┌─toStartOfQuarter(toDateTime('2023-04-21 10:20:30'))─┐
│ 2023-04-01 │
└─────────────────────────────────────────────────────┘
```
## toStartOfMonth
Rounds down a date or date with time to the first day of the month. Returns the date.
**Syntax**
```sql
toStartOfMonth(value)
```
**Arguments**
- `value` - a [Date](../data-types/date.md), [Date32](../data-types/date32.md), [DateTime](../data-types/datetime.md) or [DateTime64](../data-types/datetime64.md)
**Returned value**
- The first day of the month of the given date/time
Type: `Date`
**Example**
```sql
SELECT toStartOfMonth(toDateTime('2023-04-21 10:20:30'))
```
Result:
```response
┌─toStartOfMonth(toDateTime('2023-04-21 10:20:30'))─┐
│ 2023-04-01 │
└───────────────────────────────────────────────────┘
```
:::note
The behavior of parsing incorrect dates is implementation specific. ClickHouse may return zero date, throw an exception, or do “natural” overflow.
:::
## toLastDayOfMonth
Rounds a date or date with time to the last day of the month. Returns the date.
**Syntax**
```sql
toLastDayOfMonth(value)
```
Alias: `LAST_DAY`
**Arguments**
- `value` - a [Date](../data-types/date.md), [Date32](../data-types/date32.md), [DateTime](../data-types/datetime.md) or [DateTime64](../data-types/datetime64.md)
**Returned value**
- The last day of the month of the given date/time
Type: `Date`
**Example**
```sql
SELECT toLastDayOfMonth(toDateTime('2023-04-21 10:20:30'))
```
Result:
```response
┌─toLastDayOfMonth(toDateTime('2023-04-21 10:20:30'))─┐
│ 2023-04-30 │
└─────────────────────────────────────────────────────┘
```
## toMonday
Rounds down a date or date with time to the nearest Monday. Returns the date.
**Syntax**
```sql
toMonday(value)
```
**Arguments**
- `value` - a [Date](../data-types/date.md), [Date32](../data-types/date32.md), [DateTime](../data-types/datetime.md) or [DateTime64](../data-types/datetime64.md)
**Returned value**
- The date of the nearest Monday on or prior to the given date
Type: `Date`
**Example**
```sql
SELECT
toMonday(toDateTime('2023-04-21 10:20:30')), /* a Friday */
toMonday(toDate('2023-04-24')), /* already a Monday */
```
Result:
```response
┌─toMonday(toDateTime('2023-04-21 10:20:30'))─┬─toMonday(toDate('2023-04-24'))─┐
│ 2023-04-17 │ 2023-04-24 │
└─────────────────────────────────────────────┴────────────────────────────────┘
```
## toStartOfWeek
Rounds a date or date with time down to the nearest Sunday or Monday. Returns the date. The mode argument works exactly like the mode argument in function `toWeek()`. If no mode is specified, it defaults to 0.
**Syntax**
``` sql
toStartOfWeek(t[, mode[, timezone]])
```
**Arguments**
- `t` - a [Date](../data-types/date.md), [Date32](../data-types/date32.md), [DateTime](../data-types/datetime.md) or [DateTime64](../data-types/datetime64.md)
- `mode` - determines the first day of the week as described in the [toWeek()](date-time-functions#toweek) function
- `timezone` - Optional parameter, it behaves like any other conversion function
**Returned value**
- The date of the nearest Sunday or Monday on or prior to the given date, depending on the mode
Type: `Date`
**Example**
```sql
SELECT
toStartOfWeek(toDateTime('2023-04-21 10:20:30')), /* a Friday */
toStartOfWeek(toDateTime('2023-04-21 10:20:30'), 1), /* a Friday */
toStartOfWeek(toDate('2023-04-24')), /* a Monday */
toStartOfWeek(toDate('2023-04-24'), 1) /* a Monday */
FORMAT Vertical
```
Result:
```response
Row 1:
──────
toStartOfWeek(toDateTime('2023-04-21 10:20:30')): 2023-04-16
toStartOfWeek(toDateTime('2023-04-21 10:20:30'), 1): 2023-04-17
toStartOfWeek(toDate('2023-04-24')): 2023-04-23
toStartOfWeek(toDate('2023-04-24'), 1): 2023-04-24
```
## toLastDayOfWeek
Rounds a date or date with time up to the nearest Saturday or Sunday. Returns the date.
The mode argument works exactly like the mode argument in function `toWeek()`. If no mode is specified, mode is assumed as 0.
**Syntax**
``` sql
toLastDayOfWeek(t[, mode[, timezone]])
```
**Arguments**
- `t` - a [Date](../data-types/date.md), [Date32](../data-types/date32.md), [DateTime](../data-types/datetime.md) or [DateTime64](../data-types/datetime64.md)
- `mode` - determines the last day of the week as described in the [toWeek()](date-time-functions#toweek) function
- `timezone` - Optional parameter, it behaves like any other conversion function
**Returned value**
- The date of the nearest Sunday or Monday on or after the given date, depending on the mode
Type: `Date`
**Example**
```sql
SELECT
toLastDayOfWeek(toDateTime('2023-04-21 10:20:30')), /* a Friday */
toLastDayOfWeek(toDateTime('2023-04-21 10:20:30'), 1), /* a Friday */
toLastDayOfWeek(toDate('2023-04-22')), /* a Saturday */
toLastDayOfWeek(toDate('2023-04-22'), 1) /* a Saturday */
FORMAT Vertical
```
Result:
```response
Row 1:
──────
toLastDayOfWeek(toDateTime('2023-04-21 10:20:30')): 2023-04-22
toLastDayOfWeek(toDateTime('2023-04-21 10:20:30'), 1): 2023-04-23
toLastDayOfWeek(toDate('2023-04-22')): 2023-04-22
toLastDayOfWeek(toDate('2023-04-22'), 1): 2023-04-23
```
## toStartOfDay
Rounds down a date with time to the start of the day.
**Syntax**
```sql
toStartOfDay(value)
```
**Arguments**
- `value` - a [Date](../data-types/date.md), [Date32](../data-types/date32.md), [DateTime](../data-types/datetime.md) or [DateTime64](../data-types/datetime64.md)
**Returned value**
- The start of the day of the given date/time
Type: `DateTime`
**Example**
```sql
SELECT toStartOfDay(toDateTime('2023-04-21 10:20:30'))
```
Result:
```response
┌─toStartOfDay(toDateTime('2023-04-21 10:20:30'))─┐
│ 2023-04-21 00:00:00 │
└─────────────────────────────────────────────────┘
```
## toStartOfHour
Rounds down a date with time to the start of the hour.
**Syntax**
```sql
toStartOfHour(value)
```
**Arguments**
- `value` - a [DateTime](../data-types/datetime.md) or [DateTime64](../data-types/datetime64.md)
**Returned value**
- The start of the hour of the given date/time
Type: `DateTime`
**Example**
```sql
SELECT
toStartOfHour(toDateTime('2023-04-21 10:20:30')),
toStartOfHour(toDateTime64('2023-04-21', 6))
```
Result:
```response
┌─toStartOfHour(toDateTime('2023-04-21 10:20:30'))─┬─toStartOfHour(toDateTime64('2023-04-21', 6))─┐
│ 2023-04-21 10:00:00 │ 2023-04-21 00:00:00 │
└──────────────────────────────────────────────────┴──────────────────────────────────────────────┘
```
## toStartOfMinute
2017-04-26 19:16:38 +00:00
Rounds down a date with time to the start of the minute.
2017-04-03 19:49:50 +00:00
**Syntax**
```sql
toStartOfMinute(value)
```
**Arguments**
- `value` - a [DateTime](../data-types/datetime.md) or [DateTime64](../data-types/datetime64.md)
**Returned value**
- The start of the minute of the given date/time
Type: `DateTime`
**Example**
```sql
SELECT
toStartOfMinute(toDateTime('2023-04-21 10:20:30')),
toStartOfMinute(toDateTime64('2023-04-21 10:20:30.5300', 8))
FORMAT Vertical
```
Result:
```response
Row 1:
──────
toStartOfMinute(toDateTime('2023-04-21 10:20:30')): 2023-04-21 10:20:00
toStartOfMinute(toDateTime64('2023-04-21 10:20:30.5300', 8)): 2023-04-21 10:20:00
```
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## toStartOfSecond
Truncates sub-seconds.
**Syntax**
``` sql
toStartOfSecond(value, [timezone])
```
2021-05-28 09:14:28 +00:00
**Arguments**
- `value` — Date and time. [DateTime64](../../sql-reference/data-types/datetime64.md).
- `timezone` — [Timezone](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-timezone) for the returned value (optional). If not specified, the function uses the timezone of the `value` parameter. [String](../../sql-reference/data-types/string.md).
**Returned value**
- Input value without sub-seconds.
Type: [DateTime64](../../sql-reference/data-types/datetime64.md).
**Examples**
Query without timezone:
``` sql
WITH toDateTime64('2020-01-01 10:20:30.999', 3) AS dt64
SELECT toStartOfSecond(dt64);
```
Result:
``` text
┌───toStartOfSecond(dt64)─┐
│ 2020-01-01 10:20:30.000 │
└─────────────────────────┘
```
Query with timezone:
``` sql
WITH toDateTime64('2020-01-01 10:20:30.999', 3) AS dt64
2022-03-11 23:36:03 +00:00
SELECT toStartOfSecond(dt64, 'Asia/Istanbul');
```
Result:
``` text
2022-03-11 23:36:03 +00:00
┌─toStartOfSecond(dt64, 'Asia/Istanbul')─┐
│ 2020-01-01 13:20:30.000 │
└────────────────────────────────────────┘
```
**See also**
- [Timezone](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-timezone) server configuration parameter.
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## toStartOfFiveMinutes
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Rounds down a date with time to the start of the five-minute interval.
**Syntax**
```sql
toStartOfFiveMinutes(value)
```
**Arguments**
- `value` - a [DateTime](../data-types/datetime.md) or [DateTime64](../data-types/datetime64.md)
**Returned value**
- The start of the five-minute interval of the given date/time
Type: `DateTime`
**Example**
```sql
SELECT
toStartOfFiveMinutes(toDateTime('2023-04-21 10:17:00')),
toStartOfFiveMinutes(toDateTime('2023-04-21 10:20:00')),
toStartOfFiveMinutes(toDateTime('2023-04-21 10:23:00'))
FORMAT Vertical
```
Result:
```response
Row 1:
──────
toStartOfFiveMinutes(toDateTime('2023-04-21 10:17:00')): 2023-04-21 10:15:00
toStartOfFiveMinutes(toDateTime('2023-04-21 10:20:00')): 2023-04-21 10:20:00
toStartOfFiveMinutes(toDateTime('2023-04-21 10:23:00')): 2023-04-21 10:20:00
```
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## toStartOfTenMinutes
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Rounds down a date with time to the start of the ten-minute interval.
**Syntax**
```sql
toStartOfTenMinutes(value)
```
**Arguments**
- `value` - a [DateTime](../data-types/datetime.md) or [DateTime64](../data-types/datetime64.md)
**Returned value**
- The start of the ten-minute interval of the given date/time
Type: `DateTime`
**Example**
```sql
SELECT
toStartOfTenMinutes(toDateTime('2023-04-21 10:17:00')),
toStartOfTenMinutes(toDateTime('2023-04-21 10:20:00')),
toStartOfTenMinutes(toDateTime('2023-04-21 10:23:00'))
FORMAT Vertical
```
Result:
```response
Row 1:
──────
toStartOfTenMinutes(toDateTime('2023-04-21 10:17:00')): 2023-04-21 10:10:00
toStartOfTenMinutes(toDateTime('2023-04-21 10:20:00')): 2023-04-21 10:20:00
toStartOfTenMinutes(toDateTime('2023-04-21 10:23:00')): 2023-04-21 10:20:00
```
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## toStartOfFifteenMinutes
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Rounds down the date with time to the start of the fifteen-minute interval.
**Syntax**
```sql
toStartOfFifteenMinutes(value)
```
**Arguments**
- `value` - a [DateTime](../data-types/datetime.md) or [DateTime64](../data-types/datetime64.md)
**Returned value**
- The start of the fifteen-minute interval of the given date/time
Type: `DateTime`
**Example**
```sql
SELECT
toStartOfFifteenMinutes(toDateTime('2023-04-21 10:17:00')),
toStartOfFifteenMinutes(toDateTime('2023-04-21 10:20:00')),
toStartOfFifteenMinutes(toDateTime('2023-04-21 10:23:00'))
FORMAT Vertical
```
Result:
```response
Row 1:
──────
toStartOfFifteenMinutes(toDateTime('2023-04-21 10:17:00')): 2023-04-21 10:15:00
toStartOfFifteenMinutes(toDateTime('2023-04-21 10:20:00')): 2023-04-21 10:15:00
toStartOfFifteenMinutes(toDateTime('2023-04-21 10:23:00')): 2023-04-21 10:15:00
```
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## toStartOfInterval(date_or_date_with_time, INTERVAL x unit \[, time_zone\])
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This function generalizes other `toStartOf*()` functions. For example,
- `toStartOfInterval(t, INTERVAL 1 year)` returns the same as `toStartOfYear(t)`,
- `toStartOfInterval(t, INTERVAL 1 month)` returns the same as `toStartOfMonth(t)`,
- `toStartOfInterval(t, INTERVAL 1 day)` returns the same as `toStartOfDay(t)`,
- `toStartOfInterval(t, INTERVAL 15 minute)` returns the same as `toStartOfFifteenMinutes(t)`.
The calculation is performed relative to specific points in time:
| Interval | Start |
|-------------|------------------------|
| year | year 0 |
| quarter | 1900 Q1 |
| month | 1900 January |
| week | 1970, 1st week (01-05) |
| day | 1970-01-01 |
| hour | (*) |
| minute | 1970-01-01 00:00:00 |
| second | 1970-01-01 00:00:00 |
| millisecond | 1970-01-01 00:00:00 |
| microsecond | 1970-01-01 00:00:00 |
| nanosecond | 1970-01-01 00:00:00 |
(*) hour intervals are special: the calculation is always performed relative to 00:00:00 (midnight) of the current day. As a result, only
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hour values between 1 and 23 are useful.
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**See Also**
- [date_trunc](#date_trunc)
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## toTime
Converts a date with time to a certain fixed date, while preserving the time.
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## toRelativeYearNum
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Converts a date, or date with time, to the number of the year, starting from a certain fixed point in the past.
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## toRelativeQuarterNum
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Converts a date, or date with time, to the number of the quarter, starting from a certain fixed point in the past.
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## toRelativeMonthNum
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Converts a date, or date with time, to the number of the month, starting from a certain fixed point in the past.
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## toRelativeWeekNum
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Converts a date, or date with time, to the number of the week, starting from a certain fixed point in the past.
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## toRelativeDayNum
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Converts a date, or date with time, to the number of the day, starting from a certain fixed point in the past.
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## toRelativeHourNum
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Converts a date, or date with time, to the number of the hour, starting from a certain fixed point in the past.
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## toRelativeMinuteNum
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Converts a date, or date with time, to the number of the minute, starting from a certain fixed point in the past.
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## toRelativeSecondNum
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Converts a date, or date with time, to the number of the second, starting from a certain fixed point in the past.
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## toISOYear
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Converts a date, or date with time, to a UInt16 number containing the ISO Year number.
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## toISOWeek
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Converts a date, or date with time, to a UInt8 number containing the ISO Week number.
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## toWeek
This function returns the week number for date or datetime. The two-argument form of `toWeek()` enables you to specify whether the week starts on Sunday or Monday and whether the return value should be in the range from 0 to 53 or from 1 to 53. If the mode argument is omitted, the default mode is 0.
`toISOWeek()` is a compatibility function that is equivalent to `toWeek(date,3)`.
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The following table describes how the mode argument works.
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| Mode | First day of week | Range | Week 1 is the first week … |
|------|-------------------|-------|-------------------------------|
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| 0 | Sunday | 0-53 | with a Sunday in this year |
| 1 | Monday | 0-53 | with 4 or more days this year |
| 2 | Sunday | 1-53 | with a Sunday in this year |
| 3 | Monday | 1-53 | with 4 or more days this year |
| 4 | Sunday | 0-53 | with 4 or more days this year |
| 5 | Monday | 0-53 | with a Monday in this year |
| 6 | Sunday | 1-53 | with 4 or more days this year |
| 7 | Monday | 1-53 | with a Monday in this year |
| 8 | Sunday | 1-53 | contains January 1 |
| 9 | Monday | 1-53 | contains January 1 |
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For mode values with a meaning of “with 4 or more days this year,” weeks are numbered according to ISO 8601:1988:
- If the week containing January 1 has 4 or more days in the new year, it is week 1.
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- Otherwise, it is the last week of the previous year, and the next week is week 1.
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For mode values with a meaning of “contains January 1”, the week contains January 1 is week 1.
It does not matter how many days in the new year the week contained, even if it contained only one day.
I.e. if the last week of December contains January 1 of the next year, it will be week 1 of the next year.
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**Syntax**
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``` sql
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toWeek(t[, mode[, time_zone]])
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```
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Alias: `WEEK`
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**Arguments**
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- `t` Date or DateTime.
- `mode` Optional parameter, Range of values is \[0,9\], default is 0.
- `Timezone` Optional parameter, it behaves like any other conversion function.
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The first argument can also be specified as [String](../data-types/string.md) in a format supported by [parseDateTime64BestEffort()](type-conversion-functions.md#parsedatetime64besteffort). Support for string arguments exists only for reasons of compatibility with MySQL which is expected by certain 3rd party tools. As string argument support may in future be made dependent on new MySQL-compatibility settings and because string parsing is generally slow, it is recommended to not use it.
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**Example**
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``` sql
SELECT toDate('2016-12-27') AS date, toWeek(date) AS week0, toWeek(date,1) AS week1, toWeek(date,9) AS week9;
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```
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``` text
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┌───────date─┬─week0─┬─week1─┬─week9─┐
│ 2016-12-27 │ 52 │ 52 │ 1 │
└────────────┴───────┴───────┴───────┘
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```
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## toYearWeek
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Returns year and week for a date. The year in the result may be different from the year in the date argument for the first and the last week of the year.
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The mode argument works like the mode argument to `toWeek()`. For the single-argument syntax, a mode value of 0 is used.
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`toISOYear()` is a compatibility function that is equivalent to `intDiv(toYearWeek(date,3),100)`.
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:::warning
The week number returned by `toYearWeek()` can be different from what the `toWeek()` returns. `toWeek()` always returns week number in the context of the given year, and in case `toWeek()` returns `0`, `toYearWeek()` returns the value corresponding to the last week of previous year. See `prev_yearWeek` in example below.
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:::
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**Syntax**
``` sql
toYearWeek(t[, mode[, timezone]])
```
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Alias: `YEARWEEK`
The first argument can also be specified as [String](../data-types/string.md) in a format supported by [parseDateTime64BestEffort()](type-conversion-functions.md#parsedatetime64besteffort). Support for string arguments exists only for reasons of compatibility with MySQL which is expected by certain 3rd party tools. As string argument support may in future be made dependent on new MySQL-compatibility settings and because string parsing is generally slow, it is recommended to not use it.
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**Example**
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``` sql
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SELECT toDate('2016-12-27') AS date, toYearWeek(date) AS yearWeek0, toYearWeek(date,1) AS yearWeek1, toYearWeek(date,9) AS yearWeek9, toYearWeek(toDate('2022-01-01')) AS prev_yearWeek;
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```
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``` text
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┌───────date─┬─yearWeek0─┬─yearWeek1─┬─yearWeek9─┬─prev_yearWeek─┐
│ 2016-12-27 │ 201652 │ 201652 │ 201701 │ 202152 │
└────────────┴───────────┴───────────┴───────────┴───────────────┘
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```
## toDaysSinceYearZero
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Returns for a given date, the number of days passed since [1 January 0000](https://en.wikipedia.org/wiki/Year_zero) in the [proleptic Gregorian calendar defined by ISO 8601](https://en.wikipedia.org/wiki/Gregorian_calendar#Proleptic_Gregorian_calendar). The calculation is the same as in MySQL's [`TO_DAYS()`](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_to-days) function.
**Syntax**
``` sql
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toDaysSinceYearZero(date[, time_zone])
```
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Alias: `TO_DAYS`
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**Arguments**
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- `date` — The date to calculate the number of days passed since year zero from. [Date](../../sql-reference/data-types/date.md), [Date32](../../sql-reference/data-types/date32.md), [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md).
- `time_zone` — A String type const value or an expression represent the time zone. [String types](../../sql-reference/data-types/string.md)
**Returned value**
The number of days passed since date 0000-01-01.
Type: [UInt32](../../sql-reference/data-types/int-uint.md).
**Example**
``` sql
SELECT toDaysSinceYearZero(toDate('2023-09-08'));
```
Result:
``` text
┌─toDaysSinceYearZero(toDate('2023-09-08')))─┐
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│ 713569 │
└────────────────────────────────────────────┘
```
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**See Also**
- [fromDaysSinceYearZero](#fromDaysSinceYearZero)
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## fromDaysSinceYearZero
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Returns for a given number of days passed since [1 January 0000](https://en.wikipedia.org/wiki/Year_zero) the corresponding date in the [proleptic Gregorian calendar defined by ISO 8601](https://en.wikipedia.org/wiki/Gregorian_calendar#Proleptic_Gregorian_calendar). The calculation is the same as in MySQL's [`FROM_DAYS()`](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_from-days) function.
The result is undefined if it cannot be represented within the bounds of the [Date](../../sql-reference/data-types/date.md) type.
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**Syntax**
``` sql
fromDaysSinceYearZero(days)
```
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Alias: `FROM_DAYS`
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**Arguments**
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- `days` — The number of days passed since year zero.
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**Returned value**
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The date corresponding to the number of days passed since year zero.
Type: [Date](../../sql-reference/data-types/date.md).
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**Example**
``` sql
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SELECT fromDaysSinceYearZero(739136), fromDaysSinceYearZero(toDaysSinceYearZero(toDate('2023-09-08')));
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```
Result:
``` text
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┌─fromDaysSinceYearZero(739136)─┬─fromDaysSinceYearZero(toDaysSinceYearZero(toDate('2023-09-08')))─┐
│ 2023-09-08 │ 2023-09-08 │
└───────────────────────────────┴──────────────────────────────────────────────────────────────────┘
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```
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**See Also**
- [toDaysSinceYearZero](#toDaysSinceYearZero)
## fromDaysSinceYearZero32
Like [fromDaysSinceYearZero](#fromDaysSinceYearZero) but returns a [Date32](../../sql-reference/data-types/date32.md).
## age
Returns the `unit` component of the difference between `startdate` and `enddate`. The difference is calculated using a precision of 1 microsecond.
E.g. the difference between `2021-12-29` and `2022-01-01` is 3 days for `day` unit, 0 months for `month` unit, 0 years for `year` unit.
For an alternative to `age`, see function `date\_diff`.
**Syntax**
``` sql
age('unit', startdate, enddate, [timezone])
```
**Arguments**
- `unit` — The type of interval for result. [String](../../sql-reference/data-types/string.md).
Possible values:
- `microsecond` `microseconds` `us` `u`
- `millisecond` `milliseconds` `ms`
- `second` `seconds` `ss` `s`
- `minute` `minutes` `mi` `n`
- `hour` `hours` `hh` `h`
- `day` `days` `dd` `d`
- `week` `weeks` `wk` `ww`
- `month` `months` `mm` `m`
- `quarter` `quarters` `qq` `q`
- `year` `years` `yyyy` `yy`
- `startdate` — The first time value to subtract (the subtrahend). [Date](../../sql-reference/data-types/date.md), [Date32](../../sql-reference/data-types/date32.md), [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md).
- `enddate` — The second time value to subtract from (the minuend). [Date](../../sql-reference/data-types/date.md), [Date32](../../sql-reference/data-types/date32.md), [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md).
- `timezone` — [Timezone name](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-timezone) (optional). If specified, it is applied to both `startdate` and `enddate`. If not specified, timezones of `startdate` and `enddate` are used. If they are not the same, the result is unspecified. [String](../../sql-reference/data-types/string.md).
**Returned value**
Difference between `enddate` and `startdate` expressed in `unit`.
Type: [Int](../../sql-reference/data-types/int-uint.md).
**Example**
``` sql
SELECT age('hour', toDateTime('2018-01-01 22:30:00'), toDateTime('2018-01-02 23:00:00'));
```
Result:
``` text
┌─age('hour', toDateTime('2018-01-01 22:30:00'), toDateTime('2018-01-02 23:00:00'))─┐
│ 24 │
└───────────────────────────────────────────────────────────────────────────────────┘
```
``` sql
SELECT
toDate('2022-01-01') AS e,
toDate('2021-12-29') AS s,
age('day', s, e) AS day_age,
age('month', s, e) AS month__age,
age('year', s, e) AS year_age;
```
Result:
``` text
┌──────────e─┬──────────s─┬─day_age─┬─month__age─┬─year_age─┐
│ 2022-01-01 │ 2021-12-29 │ 3 │ 0 │ 0 │
└────────────┴────────────┴─────────┴────────────┴──────────┘
```
## date\_diff
Returns the count of the specified `unit` boundaries crossed between the `startdate` and the `enddate`.
The difference is calculated using relative units, e.g. the difference between `2021-12-29` and `2022-01-01` is 3 days for unit `day` (see [toRelativeDayNum](#torelativedaynum)), 1 month for unit `month` (see [toRelativeMonthNum](#torelativemonthnum)) and 1 year for unit `year` (see [toRelativeYearNum](#torelativeyearnum)).
If unit `week` was specified, `date\_diff` assumes that weeks start on Monday. Note that this behavior is different from that of function `toWeek()` in which weeks start by default on Sunday.
For an alternative to `date\_diff`, see function `age`.
**Syntax**
``` sql
date_diff('unit', startdate, enddate, [timezone])
```
Aliases: `dateDiff`, `DATE_DIFF`, `timestampDiff`, `timestamp_diff`, `TIMESTAMP_DIFF`.
**Arguments**
- `unit` — The type of interval for result. [String](../../sql-reference/data-types/string.md).
Possible values:
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- `microsecond` `microseconds` `us` `u`
- `millisecond` `milliseconds` `ms`
- `second` `seconds` `ss` `s`
- `minute` `minutes` `mi` `n`
- `hour` `hours` `hh` `h`
- `day` `days` `dd` `d`
- `week` `weeks` `wk` `ww`
- `month` `months` `mm` `m`
- `quarter` `quarters` `qq` `q`
- `year` `years` `yyyy` `yy`
- `startdate` — The first time value to subtract (the subtrahend). [Date](../../sql-reference/data-types/date.md), [Date32](../../sql-reference/data-types/date32.md), [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md).
- `enddate` — The second time value to subtract from (the minuend). [Date](../../sql-reference/data-types/date.md), [Date32](../../sql-reference/data-types/date32.md), [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md).
- `timezone` — [Timezone name](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-timezone) (optional). If specified, it is applied to both `startdate` and `enddate`. If not specified, timezones of `startdate` and `enddate` are used. If they are not the same, the result is unspecified. [String](../../sql-reference/data-types/string.md).
**Returned value**
Difference between `enddate` and `startdate` expressed in `unit`.
Type: [Int](../../sql-reference/data-types/int-uint.md).
**Example**
``` sql
SELECT dateDiff('hour', toDateTime('2018-01-01 22:00:00'), toDateTime('2018-01-02 23:00:00'));
```
Result:
``` text
┌─dateDiff('hour', toDateTime('2018-01-01 22:00:00'), toDateTime('2018-01-02 23:00:00'))─┐
│ 25 │
└────────────────────────────────────────────────────────────────────────────────────────┘
```
``` sql
SELECT
toDate('2022-01-01') AS e,
toDate('2021-12-29') AS s,
dateDiff('day', s, e) AS day_diff,
dateDiff('month', s, e) AS month__diff,
dateDiff('year', s, e) AS year_diff;
```
Result:
``` text
┌──────────e─┬──────────s─┬─day_diff─┬─month__diff─┬─year_diff─┐
│ 2022-01-01 │ 2021-12-29 │ 3 │ 1 │ 1 │
└────────────┴────────────┴──────────┴─────────────┴───────────┘
```
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## date\_trunc
Truncates date and time data to the specified part of date.
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**Syntax**
``` sql
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date_trunc(unit, value[, timezone])
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```
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Alias: `dateTrunc`.
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**Arguments**
- `unit` — The type of interval to truncate the result. [String Literal](../syntax.md#syntax-string-literal).
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Possible values:
- `second`
- `minute`
- `hour`
- `day`
- `week`
- `month`
- `quarter`
- `year`
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`unit` argument is case-insensitive.
- `value` — Date and time. [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md).
- `timezone` — [Timezone name](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-timezone) for the returned value (optional). If not specified, the function uses the timezone of the `value` parameter. [String](../../sql-reference/data-types/string.md).
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**Returned value**
- Value, truncated to the specified part of date.
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Type: [DateTime](../../sql-reference/data-types/datetime.md).
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**Example**
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Query without timezone:
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``` sql
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SELECT now(), date_trunc('hour', now());
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```
Result:
``` text
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┌───────────────now()─┬─date_trunc('hour', now())─┐
│ 2020-09-28 10:40:45 │ 2020-09-28 10:00:00 │
└─────────────────────┴───────────────────────────┘
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```
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Query with the specified timezone:
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```sql
SELECT now(), date_trunc('hour', now(), 'Asia/Istanbul');
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```
Result:
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```text
┌───────────────now()─┬─date_trunc('hour', now(), 'Asia/Istanbul')─┐
│ 2020-09-28 10:46:26 │ 2020-09-28 13:00:00 │
└─────────────────────┴────────────────────────────────────────────┘
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```
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**See Also**
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- [toStartOfInterval](#tostartofintervaltime-or-data-interval-x-unit-time-zone)
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## date\_add
Adds the time interval or date interval to the provided date or date with time.
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If the addition results in a value outside the bounds of the data type, the result is undefined.
**Syntax**
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``` sql
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date_add(unit, value, date)
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```
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Aliases: `dateAdd`, `DATE_ADD`.
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**Arguments**
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- `unit` — The type of interval to add. [String](../../sql-reference/data-types/string.md).
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Possible values:
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- `second`
- `minute`
- `hour`
- `day`
- `week`
- `month`
- `quarter`
- `year`
- `value` — Value of interval to add. [Int](../../sql-reference/data-types/int-uint.md).
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- `date` — The date or date with time to which `value` is added. [Date](../../sql-reference/data-types/date.md), [Date32](../../sql-reference/data-types/date32.md), [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md).
**Returned value**
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Date or date with time obtained by adding `value`, expressed in `unit`, to `date`.
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Type: [Date](../../sql-reference/data-types/date.md), [Date32](../../sql-reference/data-types/date32.md), [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md).
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**Example**
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```sql
SELECT date_add(YEAR, 3, toDate('2018-01-01'));
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```
Result:
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```text
┌─plus(toDate('2018-01-01'), toIntervalYear(3))─┐
│ 2021-01-01 │
└───────────────────────────────────────────────┘
2022-09-07 18:56:31 +00:00
```
**See Also**
- [addDate](#addDate)
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## date\_sub
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Subtracts the time interval or date interval from the provided date or date with time.
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If the subtraction results in a value outside the bounds of the data type, the result is undefined.
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**Syntax**
``` sql
date_sub(unit, value, date)
```
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Aliases: `dateSub`, `DATE_SUB`.
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**Arguments**
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- `unit` — The type of interval to subtract. Note: The unit should be unquoted.
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Possible values:
- `second`
- `minute`
- `hour`
- `day`
- `week`
- `month`
- `quarter`
- `year`
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- `value` — Value of interval to subtract. [Int](../../sql-reference/data-types/int-uint.md).
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- `date` — The date or date with time from which `value` is subtracted. [Date](../../sql-reference/data-types/date.md), [Date32](../../sql-reference/data-types/date32.md), [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md).
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**Returned value**
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Date or date with time obtained by subtracting `value`, expressed in `unit`, from `date`.
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Type: [Date](../../sql-reference/data-types/date.md), [Date32](../../sql-reference/data-types/date32.md), [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md).
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**Example**
``` sql
SELECT date_sub(YEAR, 3, toDate('2018-01-01'));
```
Result:
``` text
┌─minus(toDate('2018-01-01'), toIntervalYear(3))─┐
│ 2015-01-01 │
└────────────────────────────────────────────────┘
```
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**See Also**
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- [subDate](#subDate)
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## timestamp\_add
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Adds the specified time value with the provided date or date time value.
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If the addition results in a value outside the bounds of the data type, the result is undefined.
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**Syntax**
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``` sql
timestamp_add(date, INTERVAL value unit)
```
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Aliases: `timeStampAdd`, `TIMESTAMP_ADD`.
**Arguments**
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- `date` — Date or date with time. [Date](../../sql-reference/data-types/date.md), [Date32](../../sql-reference/data-types/date32.md), [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md).
- `value` — Value of interval to add. [Int](../../sql-reference/data-types/int-uint.md).
- `unit` — The type of interval to add. [String](../../sql-reference/data-types/string.md).
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Possible values:
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- `second`
- `minute`
- `hour`
- `day`
- `week`
- `month`
- `quarter`
- `year`
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**Returned value**
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Date or date with time with the specified `value` expressed in `unit` added to `date`.
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Type: [Date](../../sql-reference/data-types/date.md), [Date32](../../sql-reference/data-types/date32.md), [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md).
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**Example**
```sql
select timestamp_add(toDate('2018-01-01'), INTERVAL 3 MONTH);
```
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Result:
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```text
┌─plus(toDate('2018-01-01'), toIntervalMonth(3))─┐
│ 2018-04-01 │
└────────────────────────────────────────────────┘
```
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## timestamp\_sub
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Subtracts the time interval from the provided date or date with time.
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If the subtraction results in a value outside the bounds of the data type, the result is undefined.
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**Syntax**
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``` sql
timestamp_sub(unit, value, date)
```
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Aliases: `timeStampSub`, `TIMESTAMP_SUB`.
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**Arguments**
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- `unit` — The type of interval to subtract. [String](../../sql-reference/data-types/string.md).
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Possible values:
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- `second`
- `minute`
- `hour`
- `day`
- `week`
- `month`
- `quarter`
- `year`
- `value` — Value of interval to subtract. [Int](../../sql-reference/data-types/int-uint.md).
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- `date` — Date or date with time. [Date](../../sql-reference/data-types/date.md), [Date32](../../sql-reference/data-types/date32.md), [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md).
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**Returned value**
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Date or date with time obtained by subtracting `value`, expressed in `unit`, from `date`.
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Type: [Date](../../sql-reference/data-types/date.md), [Date32](../../sql-reference/data-types/date32.md), [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md).
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**Example**
```sql
select timestamp_sub(MONTH, 5, toDateTime('2018-12-18 01:02:03'));
```
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Result:
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```text
┌─minus(toDateTime('2018-12-18 01:02:03'), toIntervalMonth(5))─┐
│ 2018-07-18 01:02:03 │
└──────────────────────────────────────────────────────────────┘
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```
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## addDate
Adds the time interval to the provided date, date with time or String-encoded date / date with time.
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If the addition results in a value outside the bounds of the data type, the result is undefined.
**Syntax**
``` sql
addDate(date, interval)
```
**Arguments**
- `date` — The date or date with time to which `interval` is added. [Date](../../sql-reference/data-types/date.md), [Date32](../../sql-reference/data-types/date32.md), [DateTime](../../sql-reference/data-types/datetime.md), [DateTime64](../../sql-reference/data-types/datetime64.md), or [String](../../sql-reference/data-types/string.md)
- `interval` — Interval to add. [Interval](../../sql-reference/data-types/special-data-types/interval.md).
**Returned value**
Date or date with time obtained by adding `interval` to `date`.
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Type: [Date](../../sql-reference/data-types/date.md), [Date32](../../sql-reference/data-types/date32.md), [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md).
**Example**
```sql
SELECT addDate(toDate('2018-01-01'), INTERVAL 3 YEAR);
```
Result:
```text
┌─addDate(toDate('2018-01-01'), toIntervalYear(3))─┐
│ 2021-01-01 │
└──────────────────────────────────────────────────┘
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```
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Alias: `ADDDATE`
**See Also**
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- [date_add](#date_add)
## subDate
Subtracts the time interval from the provided date, date with time or String-encoded date / date with time.
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If the subtraction results in a value outside the bounds of the data type, the result is undefined.
**Syntax**
``` sql
subDate(date, interval)
```
**Arguments**
- `date` — The date or date with time from which `interval` is subtracted. [Date](../../sql-reference/data-types/date.md), [Date32](../../sql-reference/data-types/date32.md), [DateTime](../../sql-reference/data-types/datetime.md), [DateTime64](../../sql-reference/data-types/datetime64.md), or [String](../../sql-reference/data-types/string.md)
- `interval` — Interval to subtract. [Interval](../../sql-reference/data-types/special-data-types/interval.md).
**Returned value**
Date or date with time obtained by subtracting `interval` from `date`.
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Type: [Date](../../sql-reference/data-types/date.md), [Date32](../../sql-reference/data-types/date32.md), [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md).
**Example**
```sql
SELECT subDate(toDate('2018-01-01'), INTERVAL 3 YEAR);
```
Result:
```text
┌─subDate(toDate('2018-01-01'), toIntervalYear(3))─┐
│ 2015-01-01 │
└──────────────────────────────────────────────────┘
```
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Alias: `SUBDATE`
**See Also**
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- [date_sub](#date_sub)
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## now {#now}
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Returns the current date and time at the moment of query analysis. The function is a constant expression.
Alias: `current_timestamp`.
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**Syntax**
``` sql
now([timezone])
```
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**Arguments**
- `timezone` — [Timezone name](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-timezone) for the returned value (optional). [String](../../sql-reference/data-types/string.md).
**Returned value**
- Current date and time.
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Type: [DateTime](../../sql-reference/data-types/datetime.md).
**Example**
Query without timezone:
``` sql
SELECT now();
```
Result:
``` text
┌───────────────now()─┐
│ 2020-10-17 07:42:09 │
└─────────────────────┘
```
Query with the specified timezone:
``` sql
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SELECT now('Asia/Istanbul');
```
Result:
``` text
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┌─now('Asia/Istanbul')─┐
│ 2020-10-17 10:42:23 │
└──────────────────────┘
```
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## now64
Returns the current date and time with sub-second precision at the moment of query analysis. The function is a constant expression.
**Syntax**
``` sql
now64([scale], [timezone])
```
**Arguments**
- `scale` - Tick size (precision): 10<sup>-precision</sup> seconds. Valid range: [ 0 : 9 ]. Typically, are used - 3 (default) (milliseconds), 6 (microseconds), 9 (nanoseconds).
- `timezone` — [Timezone name](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-timezone) for the returned value (optional). [String](../../sql-reference/data-types/string.md).
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**Returned value**
- Current date and time with sub-second precision.
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Type: [DateTime64](../../sql-reference/data-types/datetime64.md).
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**Example**
``` sql
SELECT now64(), now64(9, 'Asia/Istanbul');
```
Result:
``` text
┌─────────────────now64()─┬─────now64(9, 'Asia/Istanbul')─┐
│ 2022-08-21 19:34:26.196 │ 2022-08-21 22:34:26.196542766 │
└─────────────────────────┴───────────────────────────────┘
```
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## nowInBlock {#nowInBlock}
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Returns the current date and time at the moment of processing of each block of data. In contrast to the function [now](#now), it is not a constant expression, and the returned value will be different in different blocks for long-running queries.
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It makes sense to use this function to generate the current time in long-running INSERT SELECT queries.
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**Syntax**
``` sql
nowInBlock([timezone])
```
**Arguments**
- `timezone` — [Timezone name](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-timezone) for the returned value (optional). [String](../../sql-reference/data-types/string.md).
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**Returned value**
- Current date and time at the moment of processing of each block of data.
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Type: [DateTime](../../sql-reference/data-types/datetime.md).
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**Example**
``` sql
SELECT
now(),
nowInBlock(),
sleep(1)
FROM numbers(3)
SETTINGS max_block_size = 1
FORMAT PrettyCompactMonoBlock
```
Result:
``` text
┌───────────────now()─┬────────nowInBlock()─┬─sleep(1)─┐
│ 2022-08-21 19:41:19 │ 2022-08-21 19:41:19 │ 0 │
│ 2022-08-21 19:41:19 │ 2022-08-21 19:41:20 │ 0 │
│ 2022-08-21 19:41:19 │ 2022-08-21 19:41:21 │ 0 │
└─────────────────────┴─────────────────────┴──────────┘
```
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## today {#today}
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Accepts zero arguments and returns the current date at one of the moments of query analysis.
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The same as toDate(now()).
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Aliases: `curdate`, `current_date`.
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## yesterday {#yesterday}
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Accepts zero arguments and returns yesterdays date at one of the moments of query analysis.
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The same as today() - 1.
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## timeSlot
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Rounds the time to the half hour.
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## toYYYYMM
Converts a date or date with time to a UInt32 number containing the year and month number (YYYY \* 100 + MM). Accepts a second optional timezone argument. If provided, the timezone must be a string constant.
This function is the opposite of function `YYYYMMDDToDate()`.
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**Example**
``` sql
SELECT
toYYYYMM(now(), 'US/Eastern')
```
Result:
``` text
┌─toYYYYMM(now(), 'US/Eastern')─┐
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│ 202303 │
└───────────────────────────────┘
```
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## toYYYYMMDD
Converts a date or date with time to a UInt32 number containing the year and month number (YYYY \* 10000 + MM \* 100 + DD). Accepts a second optional timezone argument. If provided, the timezone must be a string constant.
**Example**
```sql
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SELECT toYYYYMMDD(now(), 'US/Eastern')
```
Result:
```response
┌─toYYYYMMDD(now(), 'US/Eastern')─┐
│ 20230302 │
└─────────────────────────────────┘
```
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## toYYYYMMDDhhmmss
Converts a date or date with time to a UInt64 number containing the year and month number (YYYY \* 10000000000 + MM \* 100000000 + DD \* 1000000 + hh \* 10000 + mm \* 100 + ss). Accepts a second optional timezone argument. If provided, the timezone must be a string constant.
**Example**
```sql
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SELECT toYYYYMMDDhhmmss(now(), 'US/Eastern')
```
Result:
```response
┌─toYYYYMMDDhhmmss(now(), 'US/Eastern')─┐
│ 20230302112209 │
└───────────────────────────────────────┘
```
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## YYYYMMDDToDate
Converts a number containing the year, month and day number to a [Date](../../sql-reference/data-types/date.md).
This function is the opposite of function `toYYYYMMDD()`.
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The output is undefined if the input does not encode a valid Date value.
**Syntax**
```sql
YYYYMMDDToDate(yyyymmdd);
```
**Arguments**
- `yyyymmdd` - A number representing the year, month and day. [Integer](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md) or [Decimal](../../sql-reference/data-types/decimal.md).
**Returned value**
- a date created from the arguments.
Type: [Date](../../sql-reference/data-types/date.md).
**Example**
```sql
SELECT YYYYMMDDToDate(20230911);
```
Result:
```response
┌─toYYYYMMDD(20230911)─┐
│ 2023-09-11 │
└──────────────────────┘
```
## YYYYMMDDToDate32
Like function `YYYYMMDDToDate()` but produces a [Date32](../../sql-reference/data-types/date32.md).
## YYYYMMDDhhmmssToDateTime
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Converts a number containing the year, month, day, hours, minute and second number to a [DateTime](../../sql-reference/data-types/datetime.md).
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The output is undefined if the input does not encode a valid DateTime value.
This function is the opposite of function `toYYYYMMDDhhmmss()`.
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**Syntax**
```sql
YYYYMMDDhhmmssToDateTime(yyyymmddhhmmss[, timezone]);
```
**Arguments**
- `yyyymmddhhmmss` - A number representing the year, month and day. [Integer](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md) or [Decimal](../../sql-reference/data-types/decimal.md).
- `timezone` - [Timezone](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-timezone) for the returned value (optional).
**Returned value**
- a date with time created from the arguments.
Type: [DateTime](../../sql-reference/data-types/datetime.md).
**Example**
```sql
SELECT YYYYMMDDToDateTime(20230911131415);
```
Result:
```response
2023-09-15 11:26:24 +00:00
┌──────YYYYMMDDhhmmssToDateTime(20230911131415)─┐
2023-09-11 12:40:49 +00:00
│ 2023-09-11 13:14:15 │
└───────────────────────────────────────────────┘
```
## YYYYMMDDhhmmssToDateTime64
Like function `YYYYMMDDhhmmssToDate()` but produces a [DateTime64](../../sql-reference/data-types/datetime64.md).
Accepts an additional, optional `precision` parameter after the `timezone` parameter.
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## addYears, addQuarters, addMonths, addWeeks, addDays, addHours, addMinutes, addSeconds, addMilliseconds, addMicroseconds, addNanoseconds
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These functions add units of the interval specified by the function name to a date, a date with time or a string-encoded date / date with time. A date or date with time is returned.
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Example:
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``` sql
WITH
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toDate('2024-01-01') AS date,
toDateTime('2024-01-01 00:00:00') AS date_time,
'2024-01-01 00:00:00' AS date_time_string
SELECT
addYears(date, 1) AS add_years_with_date,
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addYears(date_time, 1) AS add_years_with_date_time,
addYears(date_time_string, 1) AS add_years_with_date_time_string
```
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``` text
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┌─add_years_with_date─┬─add_years_with_date_time─┬─add_years_with_date_time_string─┐
│ 2025-01-01 │ 2025-01-01 00:00:00 │ 2025-01-01 00:00:00.000 │
└─────────────────────┴──────────────────────────┴─────────────────────────────────┘
```
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## subtractYears, subtractQuarters, subtractMonths, subtractWeeks, subtractDays, subtractHours, subtractMinutes, subtractSeconds, subtractMilliseconds, subtractMicroseconds, subtractNanoseconds
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These functions subtract units of the interval specified by the function name from a date, a date with time or a string-encoded date / date with time. A date or date with time is returned.
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Example:
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``` sql
WITH
2023-10-19 21:52:23 +00:00
toDate('2024-01-01') AS date,
toDateTime('2024-01-01 00:00:00') AS date_time,
'2024-01-01 00:00:00' AS date_time_string
SELECT
subtractYears(date, 1) AS subtract_years_with_date,
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subtractYears(date_time, 1) AS subtract_years_with_date_time,
subtractYears(date_time_string, 1) AS subtract_years_with_date_time_string
```
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``` text
2023-10-19 21:52:23 +00:00
┌─subtract_years_with_date─┬─subtract_years_with_date_time─┬─subtract_years_with_date_time_string─┐
│ 2023-01-01 │ 2023-01-01 00:00:00 │ 2023-01-01 00:00:00.000 │
└──────────────────────────┴───────────────────────────────┴──────────────────────────────────────┘
```
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## timeSlots(StartTime, Duration,\[, Size\])
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For a time interval starting at StartTime and continuing for Duration seconds, it returns an array of moments in time, consisting of points from this interval rounded down to the Size in seconds. Size is an optional parameter set to 1800 (30 minutes) by default.
This is necessary, for example, when searching for pageviews in the corresponding session.
Accepts DateTime and DateTime64 as StartTime argument. For DateTime, Duration and Size arguments must be `UInt32`. For DateTime64 they must be `Decimal64`.
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Returns an array of DateTime/DateTime64 (return type matches the type of StartTime). For DateTime64, the return value's scale can differ from the scale of StartTime --- the highest scale among all given arguments is taken.
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Example:
```sql
SELECT timeSlots(toDateTime('2012-01-01 12:20:00'), toUInt32(600));
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SELECT timeSlots(toDateTime('1980-12-12 21:01:02', 'UTC'), toUInt32(600), 299);
SELECT timeSlots(toDateTime64('1980-12-12 21:01:02.1234', 4, 'UTC'), toDecimal64(600.1, 1), toDecimal64(299, 0));
2022-10-28 12:56:52 +00:00
```
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``` text
┌─timeSlots(toDateTime('2012-01-01 12:20:00'), toUInt32(600))─┐
│ ['2012-01-01 12:00:00','2012-01-01 12:30:00'] │
└─────────────────────────────────────────────────────────────┘
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┌─timeSlots(toDateTime('1980-12-12 21:01:02', 'UTC'), toUInt32(600), 299)─┐
│ ['1980-12-12 20:56:13','1980-12-12 21:01:12','1980-12-12 21:06:11'] │
└─────────────────────────────────────────────────────────────────────────┘
┌─timeSlots(toDateTime64('1980-12-12 21:01:02.1234', 4, 'UTC'), toDecimal64(600.1, 1), toDecimal64(299, 0))─┐
│ ['1980-12-12 20:56:13.0000','1980-12-12 21:01:12.0000','1980-12-12 21:06:11.0000'] │
└───────────────────────────────────────────────────────────────────────────────────────────────────────────┘
2022-06-10 11:30:17 +00:00
```
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## formatDateTime {#formatDateTime}
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Formats a Time according to the given Format string. Format is a constant expression, so you cannot have multiple formats for a single result column.
formatDateTime uses MySQL datetime format style, refer to https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_date-format.
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The opposite operation of this function is [parseDateTime](/docs/en/sql-reference/functions/type-conversion-functions.md#type_conversion_functions-parseDateTime).
Alias: `DATE_FORMAT`.
**Syntax**
``` sql
formatDateTime(Time, Format[, Timezone])
```
**Returned value(s)**
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Returns time and date values according to the determined format.
**Replacement fields**
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Using replacement fields, you can define a pattern for the resulting string. “Example” column shows formatting result for `2018-01-02 22:33:44`.
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| Placeholder | Description | Example |
|----------|---------------------------------------------------------|------------|
| %a | abbreviated weekday name (Mon-Sun) | Mon |
| %b | abbreviated month name (Jan-Dec) | Jan |
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| %c | month as an integer number (01-12), see 'Note 3' below | 01 |
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| %C | year divided by 100 and truncated to integer (00-99) | 20 |
| %d | day of the month, zero-padded (01-31) | 02 |
| %D | Short MM/DD/YY date, equivalent to %m/%d/%y | 01/02/18 |
| %e | day of the month, space-padded (1-31) | &nbsp; 2 |
| %f | fractional second, see 'Note 1' below | 1234560 |
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| %F | short YYYY-MM-DD date, equivalent to %Y-%m-%d | 2018-01-02 |
| %g | two-digit year format, aligned to ISO 8601, abbreviated from four-digit notation | 18 |
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| %G | four-digit year format for ISO week number, calculated from the week-based year [defined by the ISO 8601](https://en.wikipedia.org/wiki/ISO_8601#Week_dates) standard, normally useful only with %V | 2018 |
| %h | hour in 12h format (01-12) | 09 |
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| %H | hour in 24h format (00-23) | 22 |
| %i | minute (00-59) | 33 |
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| %I | hour in 12h format (01-12) | 10 |
| %j | day of the year (001-366) | 002 |
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| %k | hour in 24h format (00-23), see 'Note 3' below | 14 |
| %l | hour in 12h format (01-12), see 'Note 3' below | 09 |
| %m | month as an integer number (01-12) | 01 |
| %M | full month name (January-December), see 'Note 2' below | January |
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| %n | new-line character () | |
| %p | AM or PM designation | PM |
| %Q | Quarter (1-4) | 1 |
| %r | 12-hour HH:MM AM/PM time, equivalent to %h:%i %p | 10:30 PM |
| %R | 24-hour HH:MM time, equivalent to %H:%i | 22:33 |
| %s | second (00-59) | 44 |
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| %S | second (00-59) | 44 |
| %t | horizontal-tab character () | |
| %T | ISO 8601 time format (HH:MM:SS), equivalent to %H:%i:%S | 22:33:44 |
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| %u | ISO 8601 weekday as number with Monday as 1 (1-7) | 2 |
| %V | ISO 8601 week number (01-53) | 01 |
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| %w | weekday as a integer number with Sunday as 0 (0-6) | 2 |
| %W | full weekday name (Monday-Sunday) | Monday |
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| %y | Year, last two digits (00-99) | 18 |
| %Y | Year | 2018 |
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| %z | Time offset from UTC as +HHMM or -HHMM | -0500 |
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| %% | a % sign | % |
Note 1: In ClickHouse versions earlier than v23.4, `%f` prints a single zero (0) if the formatted value is a Date, Date32 or DateTime (which have no fractional seconds) or a DateTime64 with a precision of 0. The previous behavior can be restored using setting `formatdatetime_f_prints_single_zero = 1`.
Note 2: In ClickHouse versions earlier than v23.4, `%M` prints the minute (00-59) instead of the full month name (January-December). The previous behavior can be restored using setting `formatdatetime_parsedatetime_m_is_month_name = 0`.
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Note 3: In ClickHouse versions earlier than v23.11, function `parseDateTime()` required leading zeros for formatters `%c` (month) and `%l`/`%k` (hour), e.g. `07`. In later versions, the leading zero may be omitted, e.g. `7`. The previous behavior can be restored using setting `parsedatetime_parse_without_leading_zeros = 0`. Note that function `formatDateTime()` by default still prints leading zeros for `%c` and `%l`/`%k` to not break existing use cases. This behavior can be changed by setting `formatdatetime_format_without_leading_zeros = 1`.
**Example**
``` sql
SELECT formatDateTime(toDate('2010-01-04'), '%g')
```
Result:
```
┌─formatDateTime(toDate('2010-01-04'), '%g')─┐
│ 10 │
└────────────────────────────────────────────┘
```
``` sql
SELECT formatDateTime(toDateTime64('2010-01-04 12:34:56.123456', 7), '%f')
```
Result:
```
┌─formatDateTime(toDateTime64('2010-01-04 12:34:56.123456', 7), '%f')─┐
2022-12-21 20:40:30 +00:00
│ 1234560 │
└─────────────────────────────────────────────────────────────────────┘
2023-09-08 19:04:35 +00:00
```
Additionally, the `formatDateTime` function can take a third String argument containing the name of the time zone. Example: `Asia/Istanbul`. In this case, the time is formatted according to the specified time zone.
**Example**
```sql
SELECT
now() AS ts,
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time_zone,
formatDateTime(ts, '%T', time_zone) AS str_tz_time
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FROM system.time_zones
WHERE time_zone LIKE 'Europe%'
LIMIT 10
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┌──────────────────ts─┬─time_zone─────────┬─str_tz_time─┐
│ 2023-09-08 19:13:40 │ Europe/Amsterdam │ 21:13:40 │
│ 2023-09-08 19:13:40 │ Europe/Andorra │ 21:13:40 │
│ 2023-09-08 19:13:40 │ Europe/Astrakhan │ 23:13:40 │
│ 2023-09-08 19:13:40 │ Europe/Athens │ 22:13:40 │
│ 2023-09-08 19:13:40 │ Europe/Belfast │ 20:13:40 │
│ 2023-09-08 19:13:40 │ Europe/Belgrade │ 21:13:40 │
│ 2023-09-08 19:13:40 │ Europe/Berlin │ 21:13:40 │
│ 2023-09-08 19:13:40 │ Europe/Bratislava │ 21:13:40 │
│ 2023-09-08 19:13:40 │ Europe/Brussels │ 21:13:40 │
│ 2023-09-08 19:13:40 │ Europe/Bucharest │ 22:13:40 │
└─────────────────────┴───────────────────┴─────────────┘
```
**See Also**
- [formatDateTimeInJodaSyntax](##formatDateTimeInJodaSyntax)
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## formatDateTimeInJodaSyntax {#formatDateTimeInJodaSyntax}
Similar to formatDateTime, except that it formats datetime in Joda style instead of MySQL style. Refer to https://joda-time.sourceforge.net/apidocs/org/joda/time/format/DateTimeFormat.html.
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The opposite operation of this function is [parseDateTimeInJodaSyntax](/docs/en/sql-reference/functions/type-conversion-functions.md#type_conversion_functions-parseDateTimeInJodaSyntax).
**Replacement fields**
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Using replacement fields, you can define a pattern for the resulting string.
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| Placeholder | Description | Presentation | Examples |
| ----------- | ---------------------------------------- | ------------- | ---------------------------------- |
| G | era | text | AD |
| C | century of era (>=0) | number | 20 |
| Y | year of era (>=0) | year | 1996 |
| x | weekyear (not supported yet) | year | 1996 |
| w | week of weekyear (not supported yet) | number | 27 |
| e | day of week | number | 2 |
| E | day of week | text | Tuesday; Tue |
| y | year | year | 1996 |
| D | day of year | number | 189 |
| M | month of year | month | July; Jul; 07 |
| d | day of month | number | 10 |
| a | halfday of day | text | PM |
| K | hour of halfday (0~11) | number | 0 |
| h | clockhour of halfday (1~12) | number | 12 |
| H | hour of day (0~23) | number | 0 |
| k | clockhour of day (1~24) | number | 24 |
| m | minute of hour | number | 30 |
| s | second of minute | number | 55 |
| S | fraction of second (not supported yet) | number | 978 |
| z | time zone (short name not supported yet) | text | Pacific Standard Time; PST |
| Z | time zone offset/id (not supported yet) | zone | -0800; -08:00; America/Los_Angeles |
| ' | escape for text | delimiter | |
| '' | single quote | literal | ' |
**Example**
``` sql
SELECT formatDateTimeInJodaSyntax(toDateTime('2010-01-04 12:34:56'), 'yyyy-MM-dd HH:mm:ss')
```
Result:
```
┌─formatDateTimeInJodaSyntax(toDateTime('2010-01-04 12:34:56'), 'yyyy-MM-dd HH:mm:ss')─┐
│ 2010-01-04 12:34:56 │
└─────────────────────────────────────────────────────────────────────────────────────────┘
```
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## dateName
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Returns specified part of date.
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**Syntax**
``` sql
dateName(date_part, date)
```
**Arguments**
- `date_part` — Date part. Possible values: 'year', 'quarter', 'month', 'week', 'dayofyear', 'day', 'weekday', 'hour', 'minute', 'second'. [String](../../sql-reference/data-types/string.md).
- `date` — Date. [Date](../../sql-reference/data-types/date.md), [Date32](../../sql-reference/data-types/date32.md), [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md).
- `timezone` — Timezone. Optional. [String](../../sql-reference/data-types/string.md).
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**Returned value**
- The specified part of date.
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Type: [String](../../sql-reference/data-types/string.md#string)
**Example**
```sql
WITH toDateTime('2021-04-14 11:22:33') AS date_value
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SELECT
dateName('year', date_value),
dateName('month', date_value),
dateName('day', date_value);
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```
Result:
```text
┌─dateName('year', date_value)─┬─dateName('month', date_value)─┬─dateName('day', date_value)─┐
│ 2021 │ April │ 14 │
2022-08-19 18:09:40 +00:00
└──────────────────────────────┴───────────────────────────────┴─────────────────────────────┘
```
## monthName
Returns name of the month.
**Syntax**
``` sql
monthName(date)
```
**Arguments**
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- `date` — Date or date with time. [Date](../../sql-reference/data-types/date.md), [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md).
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**Returned value**
- The name of the month.
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Type: [String](../../sql-reference/data-types/string.md#string)
**Example**
```sql
WITH toDateTime('2021-04-14 11:22:33') AS date_value
SELECT monthName(date_value);
```
Result:
```text
┌─monthName(date_value)─┐
│ April │
└───────────────────────┘
2021-06-16 18:33:44 +00:00
```
## fromUnixTimestamp
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This function converts a Unix timestamp to a calendar date and a time of a day.
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It can be called in two ways:
When given a single argument of type [Integer](../../sql-reference/data-types/int-uint.md), it returns a value of type [DateTime](../../sql-reference/data-types/datetime.md), i.e. behaves like [toDateTime](../../sql-reference/functions/type-conversion-functions.md#todatetime).
Alias: `FROM_UNIXTIME`.
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**Example:**
2020-07-14 06:29:01 +00:00
```sql
SELECT fromUnixTimestamp(423543535);
2020-07-14 06:29:01 +00:00
```
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Result:
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```text
┌─fromUnixTimestamp(423543535)─┐
│ 1983-06-04 10:58:55 │
└──────────────────────────────┘
2020-07-14 06:29:01 +00:00
```
When given two or three arguments where the first argument is a value of type [Integer](../../sql-reference/data-types/int-uint.md), [Date](../../sql-reference/data-types/date.md), [Date32](../../sql-reference/data-types/date32.md), [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md), the second argument is a constant format string and the third argument is an optional constant time zone string, the function returns a value of type [String](../../sql-reference/data-types/string.md#string), i.e. it behaves like [formatDateTime](#formatdatetime). In this case, [MySQL's datetime format style](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_date-format) is used.
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**Example:**
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```sql
SELECT fromUnixTimestamp(1234334543, '%Y-%m-%d %R:%S') AS DateTime;
2020-07-14 06:29:01 +00:00
```
Result:
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```text
┌─DateTime────────────┐
│ 2009-02-11 14:42:23 │
└─────────────────────┘
```
**See Also**
- [fromUnixTimestampInJodaSyntax](##fromUnixTimestampInJodaSyntax)
## fromUnixTimestampInJodaSyntax
Same as [fromUnixTimestamp](#fromUnixTimestamp) but when called in the second way (two or three arguments), the formatting is performed using [Joda style](https://joda-time.sourceforge.net/apidocs/org/joda/time/format/DateTimeFormat.html) instead of MySQL style.
**Example:**
``` sql
SELECT fromUnixTimestampInJodaSyntax(1234334543, 'yyyy-MM-dd HH:mm:ss', 'UTC') AS DateTime;
```
Result:
```
┌─DateTime────────────┐
│ 2009-02-11 06:42:23 │
└─────────────────────┘
```
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## toModifiedJulianDay
Converts a [Proleptic Gregorian calendar](https://en.wikipedia.org/wiki/Proleptic_Gregorian_calendar) date in text form `YYYY-MM-DD` to a [Modified Julian Day](https://en.wikipedia.org/wiki/Julian_day#Variants) number in Int32. This function supports date from `0000-01-01` to `9999-12-31`. It raises an exception if the argument cannot be parsed as a date, or the date is invalid.
**Syntax**
``` sql
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toModifiedJulianDay(date)
```
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**Arguments**
- `date` — Date in text form. [String](../../sql-reference/data-types/string.md) or [FixedString](../../sql-reference/data-types/fixedstring.md).
**Returned value**
- Modified Julian Day number.
Type: [Int32](../../sql-reference/data-types/int-uint.md).
**Example**
``` sql
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SELECT toModifiedJulianDay('2020-01-01');
```
Result:
``` text
2020-12-08 15:32:55 +00:00
┌─toModifiedJulianDay('2020-01-01')─┐
│ 58849 │
└───────────────────────────────────┘
```
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## toModifiedJulianDayOrNull
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Similar to [toModifiedJulianDay()](#tomodifiedjulianday), but instead of raising exceptions it returns `NULL`.
**Syntax**
``` sql
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toModifiedJulianDayOrNull(date)
```
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**Arguments**
- `date` — Date in text form. [String](../../sql-reference/data-types/string.md) or [FixedString](../../sql-reference/data-types/fixedstring.md).
**Returned value**
- Modified Julian Day number.
Type: [Nullable(Int32)](../../sql-reference/data-types/int-uint.md).
**Example**
``` sql
2020-12-08 15:32:55 +00:00
SELECT toModifiedJulianDayOrNull('2020-01-01');
```
Result:
``` text
2020-12-08 15:32:55 +00:00
┌─toModifiedJulianDayOrNull('2020-01-01')─┐
│ 58849 │
└─────────────────────────────────────────┘
```
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## fromModifiedJulianDay
Converts a [Modified Julian Day](https://en.wikipedia.org/wiki/Julian_day#Variants) number to a [Proleptic Gregorian calendar](https://en.wikipedia.org/wiki/Proleptic_Gregorian_calendar) date in text form `YYYY-MM-DD`. This function supports day number from `-678941` to `2973119` (which represent 0000-01-01 and 9999-12-31 respectively). It raises an exception if the day number is outside of the supported range.
**Syntax**
``` sql
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fromModifiedJulianDay(day)
```
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**Arguments**
- `day` — Modified Julian Day number. [Any integral types](../../sql-reference/data-types/int-uint.md).
**Returned value**
- Date in text form.
Type: [String](../../sql-reference/data-types/string.md)
**Example**
``` sql
2020-12-08 15:32:55 +00:00
SELECT fromModifiedJulianDay(58849);
```
Result:
``` text
2020-12-08 15:32:55 +00:00
┌─fromModifiedJulianDay(58849)─┐
│ 2020-01-01 │
└──────────────────────────────┘
```
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## fromModifiedJulianDayOrNull
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Similar to [fromModifiedJulianDayOrNull()](#frommodifiedjuliandayornull), but instead of raising exceptions it returns `NULL`.
**Syntax**
``` sql
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fromModifiedJulianDayOrNull(day)
```
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**Arguments**
- `day` — Modified Julian Day number. [Any integral types](../../sql-reference/data-types/int-uint.md).
**Returned value**
- Date in text form.
Type: [Nullable(String)](../../sql-reference/data-types/string.md)
**Example**
``` sql
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SELECT fromModifiedJulianDayOrNull(58849);
```
Result:
``` text
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┌─fromModifiedJulianDayOrNull(58849)─┐
│ 2020-01-01 │
└────────────────────────────────────┘
```
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## toUTCTimestamp
Convert DateTime/DateTime64 type value from other time zone to UTC timezone timestamp
**Syntax**
``` sql
toUTCTimestamp(time_val, time_zone)
```
**Arguments**
- `time_val` — A DateTime/DateTime64 type const value or an expression . [DateTime/DateTime64 types](../../sql-reference/data-types/datetime.md)
- `time_zone` — A String type const value or an expression represent the time zone. [String types](../../sql-reference/data-types/string.md)
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**Returned value**
- DateTime/DateTime64 in text form
**Example**
``` sql
SELECT toUTCTimestamp(toDateTime('2023-03-16'), 'Asia/Shanghai');
```
Result:
``` text
┌─toUTCTimestamp(toDateTime('2023-03-16'),'Asia/Shanghai')┐
│ 2023-03-15 16:00:00 │
└─────────────────────────────────────────────────────────┘
```
## fromUTCTimestamp
Convert DateTime/DateTime64 type value from UTC timezone to other time zone timestamp
**Syntax**
``` sql
fromUTCTimestamp(time_val, time_zone)
```
**Arguments**
- `time_val` — A DateTime/DateTime64 type const value or an expression . [DateTime/DateTime64 types](../../sql-reference/data-types/datetime.md)
- `time_zone` — A String type const value or an expression represent the time zone. [String types](../../sql-reference/data-types/string.md)
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**Returned value**
- DateTime/DateTime64 in text form
**Example**
``` sql
SELECT fromUTCTimestamp(toDateTime64('2023-03-16 10:00:00', 3), 'Asia/Shanghai');
```
Result:
``` text
┌─fromUTCTimestamp(toDateTime64('2023-03-16 10:00:00',3),'Asia/Shanghai')─┐
│ 2023-03-16 18:00:00.000 │
└─────────────────────────────────────────────────────────────────────────┘
```
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## Related content
- Blog: [Working with time series data in ClickHouse](https://clickhouse.com/blog/working-with-time-series-data-and-functions-ClickHouse)