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Small docs update for toYearWeek() function

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slug	sidebar_position	sidebar_label
/en/sql-reference/functions/date-time-functions	45	Dates and Times

Functions for Working with Dates and Times

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.

Example

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

┌────────────────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 │
└─────────────────────┴────────────┴────────────┴─────────────────────┘

makeDate

Creates a Date

from a year, month and day argument, or
from a year and day of year argument.

Syntax

makeDate(year, month, day);
makeDate(year, day_of_year);

Alias:

MAKEDATE(year, month, day);
MAKEDATE(year, day_of_year);

Arguments

year — Year. Integer, Float or Decimal.
month — Month. Integer, Float or Decimal.
day — Day. Integer, Float or Decimal.
day_of_year — Day of the year. Integer, Float or Decimal.

Returned value

A date created from the arguments.

Type: Date.

Example

Create a Date from a year, month and day:

SELECT makeDate(2023, 2, 28) AS Date;

Result:

┌───────date─┐
│ 2023-02-28 │
└────────────┘

Create a Date from a year and day of year argument:

SELECT makeDate(2023, 42) AS Date;

Result:

┌───────date─┐
│ 2023-02-11 │
└────────────┘

makeDate32

Like makeDate but produces a Date32.

makeDateTime

Creates a DateTime from a year, month, day, hour, minute and second argument.

Syntax

makeDateTime(year, month, day, hour, minute, second[, timezone])

Arguments

year — Year. Integer, Float or Decimal.
month — Month. Integer, Float or Decimal.
day — Day. Integer, Float or Decimal.
hour — Hour. Integer, Float or Decimal.
minute — Minute. Integer, Float or Decimal.
second — Second. Integer, Float or Decimal.
timezone — Timezone for the returned value (optional).

Returned value

A date with time created from the arguments.

Type: DateTime.

Example

SELECT makeDateTime(2023, 2, 28, 17, 12, 33) AS DateTime;

Result:

┌────────────DateTime─┐
│ 2023-02-28 17:12:33 │
└─────────────────────┘

makeDateTime64

Like makeDateTime but produces a DateTime64.

Syntax

makeDateTime32(year, month, day, hour, minute, second[, fraction[, precision[, timezone]]])

timeZone

Returns the timezone of the current session, i.e. the value of setting 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.

Syntax

timeZone()

Alias: timezone.

Returned value

Timezone.

Type: String.

See also

serverTimeZone

serverTimeZone

Returns the timezone of the server, i.e. the value of setting 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

serverTimeZone()

Alias: serverTimezone.

Returned value

Timezone.

Type: String.

See also

timeZone

toTimeZone

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.

Syntax

toTimezone(value, timezone)

Alias: toTimezone.

Arguments

value — Time or date and time. DateTime64.
timezone — Timezone for the returned value. String. This argument is a constant, because toTimezone changes the timezone of a column (timezone is an attribute of DateTime* types).

Returned value

Date and time.

Type: DateTime.

Example

SELECT toDateTime('2019-01-01 00:00:00', 'UTC') AS time_utc,
    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;

Result:

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

timeZoneOf

Returns the timezone name of DateTime or DateTime64 data types.

Syntax

timeZoneOf(value)

Alias: timezoneOf.

Arguments

value — Date and time. DateTime or DateTime64.

Returned value

Timezone name.

Type: String.

Example

SELECT timezoneOf(now());

Result:

┌─timezoneOf(now())─┐
│ Etc/UTC           │
└───────────────────┘

timeZoneOffset

Returns the timezone offset in seconds from UTC. The function daylight saving time and historical timezone changes at the specified date and time into account. The IANA timezone database is used to calculate the offset.

Syntax

timeZoneOffset(value)

Alias: timezoneOffset.

Arguments

value — Date and time. DateTime or DateTime64.

Returned value

Offset from UTC in seconds.

Type: Int32.

Example

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:

┌────────────────Time─┬─Type─────────────────────────┬─Offset_in_seconds─┬─Offset_in_hours─┐
│ 2021-04-21 10:20:30 │ DateTime('America/New_York') │            -14400 │              -4 │
└─────────────────────┴──────────────────────────────┴───────────────────┴─────────────────┘

toYear

Converts a date or date with time to the year number (AD) as UInt16 value.

Alias: YEAR.

toQuarter

Converts a date or date with time to the quarter number as UInt8 value.

Alias: QUARTER.

toMonth

Converts a date or date with time to the month number (1-12) as UInt8 value.

Alias: MONTH.

toDayOfYear

Converts a date or date with time to the number of the day of the year (1-366) as UInt16 value.

Alias: DAYOFYEAR.

toDayOfMonth

Converts a date or date with time to the number of the day in the month (1-31) as UInt8 value.

Aliases: DAYOFMONTH, DAY.

toDayOfWeek

Converts a date or date with time to the number of the day in the week as UInt8 value.

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
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

Alias: DAYOFWEEK.

Syntax

toDayOfWeek(t[, mode[, timezone]])

toHour

Converts a date with time 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 true – even in Moscow the clocks were twice changed at a different time).

Alias: HOUR.

toMinute

Converts a date with time to the number of the minute of the hour (0-59) as UInt8 value.

Alias: MINUTE.

toSecond

Converts a date with time to the second in the minute (0-59) as UInt8 value. Leap seconds are not considered.

Alias: SECOND.

toUnixTimestamp

Converts a string, a date or a date with time to the Unix Timestamp in UInt32 representation.

If the function is called with a string, it accepts an optional timezone argument.

Syntax

toUnixTimestamp(date)
toUnixTimestamp(str, [timezone])

Returned value

Returns the unix timestamp.

Type: UInt32.

Example

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:

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 which is 0 by default.

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. :::

toStartOfYear

Rounds down a date or date with time to the first day of the year. Returns the date.

toStartOfISOYear

Rounds down a date or date with time to the first day of ISO year. Returns the date.

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.

toStartOfMonth

Rounds down a date or date with time to the first day of the month. Returns the date.

:::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.

Alias: LAST_DAY.

If toLastDayOfMonth is called with an argument of type Date greater then 2149-05-31, the result will be calculated from the argument 2149-05-31 instead.

toMonday

Rounds down a date, or date with time, to the nearest Monday. Returns the date.

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, mode is assumed as 0.

Syntax

toStartOfWeek(t[, mode[, timezone]])

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

toLastDayOfWeek(t[, mode[, timezone]])

toStartOfDay

Rounds down a date with time to the start of the day.

toStartOfHour

Rounds down a date with time to the start of the hour.

toStartOfMinute

Rounds down a date with time to the start of the minute.

toStartOfSecond

Truncates sub-seconds.

Syntax

toStartOfSecond(value, [timezone])

Arguments

value — Date and time. DateTime64.
timezone — Timezone for the returned value (optional). If not specified, the function uses the timezone of the value parameter. String.

Returned value

Input value without sub-seconds.

Type: DateTime64.

Examples

Query without timezone:

WITH toDateTime64('2020-01-01 10:20:30.999', 3) AS dt64
SELECT toStartOfSecond(dt64);

Result:

┌───toStartOfSecond(dt64)─┐
│ 2020-01-01 10:20:30.000 │
└─────────────────────────┘

Query with timezone:

WITH toDateTime64('2020-01-01 10:20:30.999', 3) AS dt64
SELECT toStartOfSecond(dt64, 'Asia/Istanbul');

Result:

┌─toStartOfSecond(dt64, 'Asia/Istanbul')─┐
│                2020-01-01 13:20:30.000 │
└────────────────────────────────────────┘

See also

Timezone server configuration parameter.

toStartOfFiveMinutes

Rounds down a date with time to the start of the five-minute interval.

toStartOfTenMinutes

Rounds down a date with time to the start of the ten-minute interval.

toStartOfFifteenMinutes

Rounds down the date with time to the start of the fifteen-minute interval.

toStartOfInterval(time_or_data, INTERVAL x unit [, time_zone])

This is a generalization of other functions named toStartOf*. 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) etc.

toTime

Converts a date with time to a certain fixed date, while preserving the time.

toRelativeYearNum

Converts a date, or date with time, to the number of the year, starting from a certain fixed point in the past.

toRelativeQuarterNum

Converts a date, or date with time, to the number of the quarter, starting from a certain fixed point in the past.

toRelativeMonthNum

Converts a date, or date with time, to the number of the month, starting from a certain fixed point in the past.

toRelativeWeekNum

Converts a date, or date with time, to the number of the week, starting from a certain fixed point in the past.

toRelativeDayNum

Converts a date, or date with time, to the number of the day, starting from a certain fixed point in the past.

toRelativeHourNum

Converts a date, or date with time, to the number of the hour, starting from a certain fixed point in the past.

toRelativeMinuteNum

Converts a date, or date with time, to the number of the minute, starting from a certain fixed point in the past.

toRelativeSecondNum

Converts a date, or date with time, to the number of the second, starting from a certain fixed point in the past.

toISOYear

Converts a date, or date with time, to a UInt16 number containing the ISO Year number.

toISOWeek

Converts a date, or date with time, to a UInt8 number containing the ISO Week number.

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).

The following table describes how the mode argument works.

Mode	First day of week	Range	Week 1 is the first week …
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

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.
Otherwise, it is the last week of the previous year, and the next week is week 1.

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.

Syntax

toWeek(t[, mode[, time_zone]])

Arguments

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.

Example

SELECT toDate('2016-12-27') AS date, toWeek(date) AS week0, toWeek(date,1) AS week1, toWeek(date,9) AS week9;

┌───────date─┬─week0─┬─week1─┬─week9─┐
│ 2016-12-27 │    52 │    52 │     1 │
└────────────┴───────┴───────┴───────┘

toYearWeek

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 mode argument works like the mode argument to toWeek(). For the single-argument syntax, a mode value of 0 is used.

toISOYear() is a compatibility function that is equivalent to intDiv(toYearWeek(date,3),100).

:::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. :::

Syntax

toYearWeek(t[, mode[, timezone]])

Example

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;

┌───────date─┬─yearWeek0─┬─yearWeek1─┬─yearWeek9─┬─prev_yearWeek─┐
│ 2016-12-27 │    201652 │    201652 │    201701 │        202152 │
└────────────┴───────────┴───────────┴───────────┴───────────────┘

age

Returns the unit component of the difference between startdate and enddate. The difference is calculated using a precision of 1 second. 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

age('unit', startdate, enddate, [timezone])

Arguments

unit — The type of interval for result. String. Possible values:
- second (possible abbreviations: ss, s)
- minute (possible abbreviations: mi, n)
- hour (possible abbreviations: hh, h)
- day (possible abbreviations: dd, d)
- week (possible abbreviations: wk, ww)
- month (possible abbreviations: mm, m)
- quarter (possible abbreviations: qq, q)
- year (possible abbreviations: yyyy, yy)
startdate — The first time value to subtract (the subtrahend). Date, Date32, DateTime or DateTime64.
enddate — The second time value to subtract from (the minuend). Date, Date32, DateTime or DateTime64.
timezone — Timezone name (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.

Returned value

Difference between enddate and startdate expressed in unit.

Type: Int.

Example

SELECT age('hour', toDateTime('2018-01-01 22:30:00'), toDateTime('2018-01-02 23:00:00'));

Result:

┌─age('hour', toDateTime('2018-01-01 22:30:00'), toDateTime('2018-01-02 23:00:00'))─┐
│                                                                                24 │
└───────────────────────────────────────────────────────────────────────────────────┘

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:

┌──────────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), 1 month for unit month (see toRelativeMonthNum) and 1 year for unit year (see 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

date_diff('unit', startdate, enddate, [timezone])

Aliases: dateDiff, DATE_DIFF, timestampDiff, timestamp_diff, TIMESTAMP_DIFF.

Arguments

unit — The type of interval for result. String. Possible values:
- second (possible abbreviations: ss, s)
- minute (possible abbreviations: mi, n)
- hour (possible abbreviations: hh, h)
- day (possible abbreviations: dd, d)
- week (possible abbreviations: wk, ww)
- month (possible abbreviations: mm, m)
- quarter (possible abbreviations: qq, q)
- year (possible abbreviations: yyyy, yy)
startdate — The first time value to subtract (the subtrahend). Date, Date32, DateTime or DateTime64.
enddate — The second time value to subtract from (the minuend). Date, Date32, DateTime or DateTime64.
timezone — Timezone name (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.

Returned value

Difference between enddate and startdate expressed in unit.

Type: Int.

Example

SELECT dateDiff('hour', toDateTime('2018-01-01 22:00:00'), toDateTime('2018-01-02 23:00:00'));

Result:

┌─dateDiff('hour', toDateTime('2018-01-01 22:00:00'), toDateTime('2018-01-02 23:00:00'))─┐
│                                                                                     25 │
└────────────────────────────────────────────────────────────────────────────────────────┘

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:

┌──────────e─┬──────────s─┬─day_diff─┬─month__diff─┬─year_diff─┐
│ 2022-01-01 │ 2021-12-29 │        3 │           1 │         1 │
└────────────┴────────────┴──────────┴─────────────┴───────────┘

date_trunc

Truncates date and time data to the specified part of date.

Syntax

date_trunc(unit, value[, timezone])

Alias: dateTrunc.

Arguments

unit — The type of interval to truncate the result. String Literal. Possible values:
- second
- minute
- hour
- day
- week
- month
- quarter
- year
value — Date and time. DateTime or DateTime64.
timezone — Timezone name for the returned value (optional). If not specified, the function uses the timezone of the value parameter. String.

Returned value

Value, truncated to the specified part of date.

Type: DateTime.

Example

Query without timezone:

SELECT now(), date_trunc('hour', now());

Result:

┌───────────────now()─┬─date_trunc('hour', now())─┐
│ 2020-09-28 10:40:45 │       2020-09-28 10:00:00 │
└─────────────────────┴───────────────────────────┘

Query with the specified timezone:

SELECT now(), date_trunc('hour', now(), 'Asia/Istanbul');

Result:

┌───────────────now()─┬─date_trunc('hour', now(), 'Asia/Istanbul')─┐
│ 2020-09-28 10:46:26 │                        2020-09-28 13:00:00 │
└─────────────────────┴────────────────────────────────────────────┘

See Also

toStartOfInterval

date_add

Adds the time interval or date interval to the provided date or date with time.

Syntax

date_add(unit, value, date)

Aliases: dateAdd, DATE_ADD.

Arguments

unit — The type of interval to add. String. Possible values:
- second
- minute
- hour
- day
- week
- month
- quarter
- year
value — Value of interval to add. Int.
date — The date or date with time to which value is added. Date or DateTime.

Returned value

Date or date with time obtained by adding value, expressed in unit, to date.

Type: Date or DateTime.

Example

SELECT date_add(YEAR, 3, toDate('2018-01-01'));

Result:

┌─plus(toDate('2018-01-01'), toIntervalYear(3))─┐
│                                    2021-01-01 │
└───────────────────────────────────────────────┘

date_sub

Subtracts the time interval or date interval from the provided date or date with time.

Syntax

date_sub(unit, value, date)

Aliases: dateSub, DATE_SUB.

Arguments

unit — The type of interval to subtract. Note: The unit should be unquoted.

Possible values:
- second
- minute
- hour
- day
- week
- month
- quarter
- year
value — Value of interval to subtract. Int.
date — The date or date with time from which value is subtracted. Date or DateTime.

Returned value

Date or date with time obtained by subtracting value, expressed in unit, from date.

Type: Date or DateTime.

Example

SELECT date_sub(YEAR, 3, toDate('2018-01-01'));

Result:

┌─minus(toDate('2018-01-01'), toIntervalYear(3))─┐
│                                     2015-01-01 │
└────────────────────────────────────────────────┘

timestamp_add

Adds the specified time value with the provided date or date time value.

Syntax

timestamp_add(date, INTERVAL value unit)

Aliases: timeStampAdd, TIMESTAMP_ADD.

Arguments

date — Date or date with time. Date or DateTime.
value — Value of interval to add. Int.
unit — The type of interval to add. String. Possible values:
- second
- minute
- hour
- day
- week
- month
- quarter
- year

Returned value

Date or date with time with the specified value expressed in unit added to date.

Type: Date or DateTime.

Example

select timestamp_add(toDate('2018-01-01'), INTERVAL 3 MONTH);

Result:

┌─plus(toDate('2018-01-01'), toIntervalMonth(3))─┐
│                                     2018-04-01 │
└────────────────────────────────────────────────┘

timestamp_sub

Subtracts the time interval from the provided date or date with time.

Syntax

timestamp_sub(unit, value, date)

Aliases: timeStampSub, TIMESTAMP_SUB.

Arguments

unit — The type of interval to subtract. String. Possible values:
- second
- minute
- hour
- day
- week
- month
- quarter
- year
value — Value of interval to subtract. Int.
date — Date or date with time. Date or DateTime.

Returned value

Date or date with time obtained by subtracting value, expressed in unit, from date.

Type: Date or DateTime.

Example

select timestamp_sub(MONTH, 5, toDateTime('2018-12-18 01:02:03'));

Result:

┌─minus(toDateTime('2018-12-18 01:02:03'), toIntervalMonth(5))─┐
│                                          2018-07-18 01:02:03 │
└──────────────────────────────────────────────────────────────┘

now

Returns the current date and time at the moment of query analysis. The function is a constant expression.

Syntax

now([timezone])

Arguments

timezone — Timezone name for the returned value (optional). String.

Returned value

Current date and time.

Type: DateTime.

Example

Query without timezone:

SELECT now();

Result:

┌───────────────now()─┐
│ 2020-10-17 07:42:09 │
└─────────────────────┘

Query with the specified timezone:

SELECT now('Asia/Istanbul');

Result:

┌─now('Asia/Istanbul')─┐
│  2020-10-17 10:42:23 │
└──────────────────────┘

now64

Returns the current date and time with sub-second precision at the moment of query analysis. The function is a constant expression.

Syntax

now64([scale], [timezone])

Arguments

scale - Tick size (precision): 10^-precision seconds. Valid range: [ 0 : 9 ]. Typically are used - 3 (default) (milliseconds), 6 (microseconds), 9 (nanoseconds).
timezone — Timezone name for the returned value (optional). String.

Returned value

Current date and time with sub-second precision.

Type: DateTime64.

Example

SELECT now64(), now64(9, 'Asia/Istanbul');

Result:

┌─────────────────now64()─┬─────now64(9, 'Asia/Istanbul')─┐
│ 2022-08-21 19:34:26.196 │ 2022-08-21 22:34:26.196542766 │
└─────────────────────────┴───────────────────────────────┘

nowInBlock

Returns the current date and time at the moment of processing of each block of data. In contrast to the function now, it is not a constant expression, and the returned value will be different in different blocks for long-running queries.

It makes sense to use this function to generate the current time in long-running INSERT SELECT queries.

Syntax

nowInBlock([timezone])

Arguments

timezone — Timezone name for the returned value (optional). String.

Returned value

Current date and time at the moment of processing of each block of data.

Type: DateTime.

Example

SELECT
    now(),
    nowInBlock(),
    sleep(1)
FROM numbers(3)
SETTINGS max_block_size = 1
FORMAT PrettyCompactMonoBlock

Result:

┌───────────────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 │
└─────────────────────┴─────────────────────┴──────────┘

today

Accepts zero arguments and returns the current date at one of the moments of query analysis. The same as ‘toDate(now())’.

yesterday

Accepts zero arguments and returns yesterday’s date at one of the moments of query analysis. The same as ‘today() - 1’.

timeSlot

Rounds the time to the half hour.

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.

Example

SELECT
    toYYYYMM(now(), 'US/Eastern')

Result:

┌─toYYYYMM(now(), 'US/Eastern')─┐
│                        202303 │
└───────────────────────────────┘

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

SELECT
    toYYYYMMDD(now(), 'US/Eastern')

Result:

┌─toYYYYMMDD(now(), 'US/Eastern')─┐
│                        20230302 │
└─────────────────────────────────┘

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

SELECT
    toYYYYMMDDhhmmss(now(), 'US/Eastern')

Result:

┌─toYYYYMMDDhhmmss(now(), 'US/Eastern')─┐
│                        20230302112209 │
└───────────────────────────────────────┘

addYears, addMonths, addWeeks, addDays, addHours, addMinutes, addSeconds, addQuarters

Function adds a Date/DateTime interval to a Date/DateTime and then return the Date/DateTime. For example:

WITH
    toDate('2018-01-01') AS date,
    toDateTime('2018-01-01 00:00:00') AS date_time
SELECT
    addYears(date, 1) AS add_years_with_date,
    addYears(date_time, 1) AS add_years_with_date_time

┌─add_years_with_date─┬─add_years_with_date_time─┐
│          2019-01-01 │      2019-01-01 00:00:00 │
└─────────────────────┴──────────────────────────┘

subtractYears, subtractMonths, subtractWeeks, subtractDays, subtractHours, subtractMinutes, subtractSeconds, subtractQuarters

Function subtract a Date/DateTime interval to a Date/DateTime and then return the Date/DateTime. For example:

WITH
    toDate('2019-01-01') AS date,
    toDateTime('2019-01-01 00:00:00') AS date_time
SELECT
    subtractYears(date, 1) AS subtract_years_with_date,
    subtractYears(date_time, 1) AS subtract_years_with_date_time

┌─subtract_years_with_date─┬─subtract_years_with_date_time─┐
│               2018-01-01 │           2018-01-01 00:00:00 │
└──────────────────────────┴───────────────────────────────┘

timeSlots(StartTime, Duration,[, Size])

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.

Example:

SELECT timeSlots(toDateTime('2012-01-01 12:20:00'), toUInt32(600));
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));

┌─timeSlots(toDateTime('2012-01-01 12:20:00'), toUInt32(600))─┐
│ ['2012-01-01 12:00:00','2012-01-01 12:30:00']               │
└─────────────────────────────────────────────────────────────┘
┌─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']                        │
└───────────────────────────────────────────────────────────────────────────────────────────────────────────┘

formatDateTime

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.

The opposite operation of this function is parseDateTime.

Alias: DATE_FORMAT.

Syntax

formatDateTime(Time, Format[, Timezone])

Returned value(s)

Returns time and date values according to the determined format.

Replacement fields Using replacement fields, you can define a pattern for the resulting string. “Example” column shows formatting result for 2018-01-02 22:33:44.

Placeholder	Description	Example
%a	abbreviated weekday name (Mon-Sun)	Mon
%b	abbreviated month name (Jan-Dec)	Jan
%c	month as an integer number (01-12)	01
%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)	2
%f	fractional second, see 'Note 1' below	1234560
%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
%G	four-digit year format for ISO week number, calculated from the week-based year defined by the ISO 8601 standard, normally useful only with %V	2018
%h	hour in 12h format (01-12)	09
%H	hour in 24h format (00-23)	22
%i	minute (00-59)	33
%I	hour in 12h format (01-12)	10
%j	day of the year (001-366)	002
%k	hour in 24h format (00-23)	22
%l	hour in 12h format (01-12)	09
%m	month as an integer number (01-12)	01
%M	full month name (January-December), see 'Note 2' below	January
%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
%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
%u	ISO 8601 weekday as number with Monday as 1 (1-7)	2
%V	ISO 8601 week number (01-53)	01
%w	weekday as a integer number with Sunday as 0 (0-6)	2
%W	full weekday name (Monday-Sunday)	Monday
%y	Year, last two digits (00-99)	18
%Y	Year	2018
%z	Time offset from UTC as +HHMM or -HHMM	-0500
%%	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.

Example

SELECT formatDateTime(toDate('2010-01-04'), '%g')

Result:

┌─formatDateTime(toDate('2010-01-04'), '%g')─┐
│ 10                                         │
└────────────────────────────────────────────┘

SELECT formatDateTime(toDateTime64('2010-01-04 12:34:56.123456', 7), '%f')

Result:

┌─formatDateTime(toDateTime64('2010-01-04 12:34:56.123456', 7), '%f')─┐
│ 1234560                                                             │
└─────────────────────────────────────────────────────────────────────┘

See Also

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.

The opposite operation of this function is parseDateTimeInJodaSyntax.

Replacement fields

Using replacement fields, you can define a pattern for the resulting string.

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

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                                                                     │
└─────────────────────────────────────────────────────────────────────────────────────────┘

dateName

Returns specified part of date.

Syntax

dateName(date_part, date)

Arguments

date_part — Date part. Possible values: 'year', 'quarter', 'month', 'week', 'dayofyear', 'day', 'weekday', 'hour', 'minute', 'second'. String.
date — Date. Date, Date32, DateTime or DateTime64.
timezone — Timezone. Optional. String.

Returned value

The specified part of date.

Type: String

Example

WITH toDateTime('2021-04-14 11:22:33') AS date_value
SELECT
    dateName('year', date_value),
    dateName('month', date_value),
    dateName('day', date_value);

Result:

┌─dateName('year', date_value)─┬─dateName('month', date_value)─┬─dateName('day', date_value)─┐
│ 2021                         │ April                         │ 14                          │
└──────────────────────────────┴───────────────────────────────┴─────────────────────────────┘

monthName

Returns name of the month.

Syntax

monthName(date)

Arguments

date — Date or date with time. Date or DateTime.

Returned value

The name of the month.

Type: String

Example

WITH toDateTime('2021-04-14 11:22:33') AS date_value
SELECT monthName(date_value);

Result:

┌─monthName(date_value)─┐
│ April                 │
└───────────────────────┘

fromUnixTimestamp

Function converts Unix timestamp to a calendar date and a time of a day. When there is only a single argument of Integer type, it acts in the same way as toDateTime and return DateTime type.

fromUnixTimestamp uses MySQL datetime format style, refer to https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_date-format.

Alias: FROM_UNIXTIME.

Example:

SELECT fromUnixTimestamp(423543535);

Result:

┌─fromUnixTimestamp(423543535)─┐
│          1983-06-04 10:58:55 │
└──────────────────────────────┘

When there are two or three arguments, the first an Integer, Date, Date32, DateTime or DateTime64, the second a constant format string and the third an optional constant time zone string — it acts in the same way as formatDateTime and return String type.

For example:

SELECT fromUnixTimestamp(1234334543, '%Y-%m-%d %R:%S') AS DateTime;

┌─DateTime────────────┐
│ 2009-02-11 14:42:23 │
└─────────────────────┘

See Also

fromUnixTimestampInJodaSyntax

fromUnixTimestampInJodaSyntax

Similar to fromUnixTimestamp, except that it formats time in Joda style instead of MySQL style. Refer to https://joda-time.sourceforge.net/apidocs/org/joda/time/format/DateTimeFormat.html.

Example:

SELECT fromUnixTimestampInJodaSyntax(1669804872, 'yyyy-MM-dd HH:mm:ss', 'UTC');

Result:

┌─fromUnixTimestampInJodaSyntax(1669804872, 'yyyy-MM-dd HH:mm:ss', 'UTC')────┐
│ 2022-11-30 10:41:12                                                        │
└────────────────────────────────────────────────────────────────────────────┘

toModifiedJulianDay

Converts a Proleptic Gregorian calendar date in text form YYYY-MM-DD to a Modified Julian Day 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

toModifiedJulianDay(date)

Arguments

date — Date in text form. String or FixedString.

Returned value

Modified Julian Day number.

Type: Int32.

Example

SELECT toModifiedJulianDay('2020-01-01');

Result:

┌─toModifiedJulianDay('2020-01-01')─┐
│                             58849 │
└───────────────────────────────────┘

toModifiedJulianDayOrNull

Similar to toModifiedJulianDay(), but instead of raising exceptions it returns NULL.

Syntax

toModifiedJulianDayOrNull(date)

Arguments

date — Date in text form. String or FixedString.

Returned value

Modified Julian Day number.

Type: Nullable(Int32).

Example

SELECT toModifiedJulianDayOrNull('2020-01-01');

Result:

┌─toModifiedJulianDayOrNull('2020-01-01')─┐
│                                   58849 │
└─────────────────────────────────────────┘

fromModifiedJulianDay

Converts a Modified Julian Day number to a 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

fromModifiedJulianDay(day)

Arguments

day — Modified Julian Day number. Any integral types.

Returned value

Date in text form.

Type: String

Example

SELECT fromModifiedJulianDay(58849);

Result:

┌─fromModifiedJulianDay(58849)─┐
│ 2020-01-01                   │
└──────────────────────────────┘

fromModifiedJulianDayOrNull

Similar to fromModifiedJulianDayOrNull(), but instead of raising exceptions it returns NULL.

Syntax

fromModifiedJulianDayOrNull(day)

Arguments

day — Modified Julian Day number. Any integral types.

Returned value

Date in text form.

Type: Nullable(String)

Example

SELECT fromModifiedJulianDayOrNull(58849);

Result:

┌─fromModifiedJulianDayOrNull(58849)─┐
│ 2020-01-01                         │
└────────────────────────────────────┘

Blog: Working with time series data in ClickHouse

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Functions for Working with Dates and Times

makeDate

makeDate32

makeDateTime

makeDateTime64

timeZone

serverTimeZone

toTimeZone

timeZoneOf

timeZoneOffset

toYear

toQuarter

toMonth

toDayOfYear

toDayOfMonth

toDayOfWeek

toHour

toMinute

toSecond

toUnixTimestamp

toStartOfYear

toStartOfISOYear

toStartOfQuarter

toStartOfMonth

toLastDayOfMonth

toMonday

toStartOfWeek

toLastDayOfWeek

toStartOfDay

toStartOfHour

toStartOfMinute

toStartOfSecond

toStartOfFiveMinutes

toStartOfTenMinutes

toStartOfFifteenMinutes

toStartOfInterval(time_or_data, INTERVAL x unit [, time_zone])

toTime

toRelativeYearNum

toRelativeQuarterNum

toRelativeMonthNum

toRelativeWeekNum

toRelativeDayNum

toRelativeHourNum

toRelativeMinuteNum

toRelativeSecondNum

toISOYear

toISOWeek

toWeek

toYearWeek

age

date_diff

date_trunc

date_add

date_sub

timestamp_add

timestamp_sub

now

now64

nowInBlock

today

yesterday

timeSlot

toYYYYMM

toYYYYMMDD

toYYYYMMDDhhmmss

addYears, addMonths, addWeeks, addDays, addHours, addMinutes, addSeconds, addQuarters

subtractYears, subtractMonths, subtractWeeks, subtractDays, subtractHours, subtractMinutes, subtractSeconds, subtractQuarters

timeSlots(StartTime, Duration,[, Size])

formatDateTime

formatDateTimeInJodaSyntax

dateName

monthName

fromUnixTimestamp

fromUnixTimestampInJodaSyntax

toModifiedJulianDay

toModifiedJulianDayOrNull

fromModifiedJulianDay

fromModifiedJulianDayOrNull

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