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.
-`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).
-`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).
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.
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.
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.
-`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).
Returns the timezone name of [DateTime](../../sql-reference/data-types/datetime.md) or [DateTime64](../../sql-reference/data-types/datetime64.md) data types.
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.
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)
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
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
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
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
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.
-`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.
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
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
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
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.
* 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.
* 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`.
-`value` - a [Date](../data-types/date.md), [Date32](../data-types/date32.md), [DateTime](../data-types/datetime.md) or [DateTime64](../data-types/datetime64.md)
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).)
-`value` - a [Date](../data-types/date.md), [Date32](../data-types/date32.md), [DateTime](../data-types/datetime.md) or [DateTime64](../data-types/datetime64.md)
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
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
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
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 */
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 */
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 */
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)
-`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).
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)`.
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.
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.
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.
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.
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.
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;
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.
-`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).
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.
-`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).
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`.
-`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).
-`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).
-`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).
-`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).
-`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).
-`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).
-`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)
-`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)
-`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).
-`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).
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.
-`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).
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.
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.
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.
Converts a number containing the year, month and day number to a [Date](../../sql-reference/data-types/date.md).
This functions is the opposite of function `toYYYYMMDD()`.
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).
-`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).
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.
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.
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`.
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.
The opposite operation of this function is [parseDateTime](/docs/en/sql-reference/functions/type-conversion-functions.md#type_conversion_functions-parseDateTime).
| %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 |
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`.
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`.
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.
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.
The opposite operation of this function is [parseDateTimeInJodaSyntax](/docs/en/sql-reference/functions/type-conversion-functions.md#type_conversion_functions-parseDateTimeInJodaSyntax).
-`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).
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).
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.
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.
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.
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.