Datetime functions

Learn how to use and combine different timespan functions in APL

The table summarizes the datetime functions available in APL.

Name	Description
ago	Subtracts the given timespan from the current UTC clock time.
datetime_add	Calculates a new datetime from a specified datepart multiplied by a specified amount, added to a specified datetime.
datetime_part	Extracts the requested date part as an integer value.
datetime_diff	Calculates calendarian difference between two datetime values.
dayofmonth	Returns the integer number representing the day number of the given month
dayofweek	Returns the integer number of days since the preceding Sunday, as a timespan.
dayofyear	Returns the integer number represents the day number of the given year.
endofyear	Returns the end of the year containing the date
getmonth	Get the month number (1-12) from a datetime.
getyear	Returns the year part of the datetime argument.
hourofday	Returns the integer number representing the hour number of the given date.
endofday	Returns the end of the day containing the date.
now	Returns the current UTC clock time, optionally offset by a given timespan.
endofmonth	Returns the end of the month containing the date.
endofweek	Returns the end of the week containing the date.
monthofyear	Returns the integer number represents the month number of the given year.
startofday	Returns the start of the day containing the date.
startofmonth	Returns the start of the month containing the date.
startofweek	Returns the start of the week containing the date.
startofyear	Returns the start of the year containing the date.
unixtime_microseconds_todatetime	Converts a Unix timestamp expressed in whole microseconds to an APL datetime value.
unixtime_milliseconds_todatetime	Converts a Unix timestamp expressed in whole milliseconds to an APL datetime value.
unixtime_nanoseconds_todatetime	Converts a Unix timestamp expressed in whole nanoseconds to an APL datetime value.
unixtime_seconds_todatetime	Converts a Unix timestamp expressed in whole seconds to an APL datetime value.

We support the ISO 8601 format, which is the standard format for representing dates and times in the Gregorian calendar. Check them out here

ago

Subtracts the given timespan from the current UTC clock time.

Arguments

• Interval to subtract from the current UTC clock time

Returns

now() - a_timespan

Example

ago(6h)

Run in Playground

• Result:

{
  "date_time_functions": "2023-09-11T20:12:39Z"
}

ago(3d)

Run in Playground

• Result:

{
  "date_time_functions": "2023-09-09T02:13:29Z"
}

datetime_add

Calculates a new datetime from a specified datepart multiplied by a specified amount, added to a specified datetime.

Arguments

• period: string.
• amount: integer.
• datetime: datetime value.

Returns

A date after a certain time/date interval has been added.

Example

datetime_add(period,amount,datetime)

['sample-http-logs']
| project new_datetime = datetime_add( "month", 1, datetime(2016-10-06))

Run in Playground

• Result:

{
  "new_datetime": "2016-11-06T00:00:00Z"
}

datetime_part

Extracts the requested date part as an integer value.

Arguments

• date: datetime
• part: string

Returns

An integer representing the extracted part.

Examples

datetime_part(part,datetime)

['sample-http-logs']
| project new_datetime = datetime_part("Day", datetime(2016-06-26T08:20:03.123456Z))

Run in Playground

• Result:

{
  "new_datetime": 26
}

datetime_diff

Calculates calendarian difference between two datetime values.

Arguments

• period: string.
• datetime_1: datetime value.
• datetime_2: datetime value.

Returns

An integer, which represents amount of periods in the result of subtraction (datetime_1 - datetime_2).

Example

datetime_diff(period,datetime_1,datetime_2)

['sample-http-logs']
| project new_datetime = datetime_diff("week", datetime(2019-06-26T08:20:03.123456Z), datetime(2014-06-26T08:19:03.123456Z))

Run in Playground

• Result:

{
  "new_datetime": 260
}

['sample-http-logs']
| project new_datetime = datetime_diff("week", datetime(2015-11-08), datetime(2014-11-08))

Run in Playground

• Result:

{
  "new_datetime": 52
}

dayofmonth

Returns the integer number representing the day number of the given month

Arguments

• a_date: A datetime

Returns

day number of the given month.

Example

dayofmonth(a_date)

['sample-http-logs']
| project day_of_the_month = dayofmonth(datetime(2017-11-30))

Run in Playground

• Result:

{
  "day_of_the_month": 30
}

dayofweek

Returns the integer number of days since the preceding Sunday, as a timespan.

Arguments

• a_date: A datetime.

Returns

The timespan since midnight at the beginning of the preceding Sunday, rounded down to an integer number of days.

Example

dayofweek(a_date)

['sample-http-logs']
| project day_of_the_week = dayofweek(datetime(2019-05-18))

Run in Playground

• Result:

{
  "day_of_the_week": 6
}

dayofyear

Returns the integer number represents the day number of the given year.

Arguments

• a_date: A datetime.

Returns

day number of the given year.

Example

dayofyear(a_date)

['sample-http-logs']
| project day_of_the_year = dayofyear(datetime(2020-07-20))

Run in Playground

• Result:

{
  "day_of_the_year": 202
}

endofyear

Returns the end of the year containing the date

Arguments

• date: The input date.

Returns

A datetime representing the end of the year for the given date value

Example

endofyear(date)

['sample-http-logs']
| extend end_of_the_year = endofyear(datetime(2016-06-26T08:20))

Run in Playground

• Result:

{
  "end_of_the_year": "2016-12-31T23:59:59.999999999Z"
}

getmonth

Get the month number (1-12) from a datetime.

['sample-http-logs']
| extend get_specific_month = getmonth(datetime(2020-07-26T08:20))

getyear

Returns the year part of the datetime argument.

Example

getyear(datetime())

['sample-http-logs']
| project get_specific_year = getyear(datetime(2020-07-26))

Run in Playground

• Result:

{
  "get_specific_year": 2020
}

hourofday

Returns the integer number representing the hour number of the given date

Arguments

• a_date: A datetime.

Returns

hour number of the day (0-23).

Example

hourofday(a_date)

['sample-http-logs']
| project get_specific_hour = hourofday(datetime(2016-06-26T08:20:03.123456Z))

Run in Playground

• Result:

{
  "get_specific_hour": 8
}

endofday

Returns the end of the day containing the date

Arguments

• date: The input date.

Returns

A datetime representing the end of the day for the given date value.

Example

endofday(date)

['sample-http-logs']
| project end_of_day_series = endofday(datetime(2016-06-26T08:20:03.123456Z))

Run in Playground

• Result:

{
  "end_of_day_series": "2016-06-26T23:59:59.999999999Z"
}

now

Returns the current UTC clock time, optionally offset by a given timespan. This function can be used multiple times in a statement and the clock time being referenced will be the same for all instances.

Arguments

• offset: A timespan, added to the current UTC clock time. Default: 0.

Returns

The current UTC clock time as a datetime.

Example

now([offset])

['sample-http-logs']
| project returns_clock_time = now(-5d)

Run in Playground

• Result:

{
  "returns_clock_time": "2023-09-07T02:54:50Z"
}

endofmonth

Returns the end of the month containing the date

Arguments

• date: The input date.

Returns

A datetime representing the end of the month for the given date value.

Example

endofmonth(date)

['sample-http-logs']
| project end_of_the_month = endofmonth(datetime(2016-06-26T08:20))

Run in Playground

• Result:

{
  "end_of_the_month": "2016-06-30T23:59:59.999999999Z"
}

endofweek

Returns the end of the week containing the date

Arguments

• date: The input date.

Returns

A datetime representing the end of the week for the given date value

Example

endofweek(date)

['sample-http-logs']
| project end_of_the_week = endofweek(datetime(2019-04-18T08:20))

Run in Playground

• Result:

{
  "end_of_the_week": "2019-04-20T23:59:59.999999999Z"
}

monthofyear

Returns the integer number represents the month number of the given year.

Arguments

• date: A datetime.

Returns

month number of the given year.

Example

monthofyear(datetime("2018-11-21"))

['sample-http-logs']
| project month_of_the_year = monthofyear(datetime(2018-11-11))

Run in Playground

• Result:

{
  "month_of_the_year": 11
}

startofday

Returns the start of the day containing the date

Arguments

• date: The input date.

Returns

A datetime representing the start of the day for the given date value

Examples

startofday(datetime(2020-08-31))

['sample-http-logs']
| project start_of_the_day = startofday(datetime(2018-11-11))

Run in Playground

• Result:

{
  "start_of_the_day": "2018-11-11T00:00:00Z"
}

startofmonth

Returns the start of the month containing the date

Arguments

• date: The input date.

Returns

A datetime representing the start of the month for the given date value

Example

['github-issues-event']
| project start_of_the_month =  startofmonth(datetime(2020-08-01))

Run in Playground

• Result:

{
  "start_of_the_month": "2020-08-01T00:00:00Z"
}

['hackernews']
| extend start_of_the_month = startofmonth(datetime(2020-08-01))

Run in Playground

• Result:

{
  "start_of_the_month": "2020-08-01T00:00:00Z"
}

startofweek

Returns the start of the week containing the date

Start of the week is considered to be a Sunday.

Arguments

• date: The input date.

Returns

A datetime representing the start of the week for the given date value

Examples

['github-issues-event']
| extend start_of_the_week =  startofweek(datetime(2020-08-01))

Run in Playground

• Result:

{
  "start_of_the_week": "2020-07-26T00:00:00Z"
}

['hackernews']
| extend start_of_the_week = startofweek(datetime(2020-08-01))

Run in Playground

• Result:

{
  "start_of_the_week": "2020-07-26T00:00:00Z"
}

['sample-http-logs']
| extend start_of_the_week = startofweek(datetime(2018-06-11T00:00:00Z))

startofyear

Returns the start of the year containing the date

Arguments

• date: The input date.

Returns

A datetime representing the start of the year for the given date value

Examples

['sample-http-logs']
| project yearStart = startofyear(datetime(2019-04-03))

Run in Playground

• Result:

{
  "yearStart": "2019-01-01T00:00:00Z"
}

['sample-http-logs']
| project yearStart = startofyear(datetime(2019-10-09 01:00:00.0000000))

Run in Playground

• Result:

{
  "yearStart": "2019-01-01T00:00:00Z"
}