Datetime functions

Learn how to use and combine different timespan functions in APL

DateTime/ Timespan functions

Function 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

• 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"
}