Datetime functions

Learn how to use and combine different datetime 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_diff	Calculates the calendarian difference between two datetime values.
datetime_part	Extracts the requested date part as an integer value.
dayofmonth	Returns the integer number representing the day number of the given month.
dayofweek	Returns the integer number of days since the preceding Sunday.
dayofyear	Returns the integer number representing the day number of the given year.
endofday	Returns the end of the day containing the date.
endofmonth	Returns the end of the month containing the date.
endofweek	Returns the end of the week containing the date.
endofyear	Returns the end of the year containing the date.
getmonth	Returns 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.
monthofyear	Returns the integer number representing the month number of the given year.
now	Returns the current UTC clock time, optionally offset by a given timespan.
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.
week_of_year	Returns the ISO 8601 week number from a datetime expression.

Axiom supports the ISO 8601 format which is the standard format for representing dates and times in the Gregorian calendar. For more information, see Supported formats.

Format datetime values as strings

To display a datetime value as a formatted string, use tostring(). By default, tostring() returns the datetime in ISO 8601 format.

['sample-http-logs']
| summarize earliest = min(_time)
| extend earliest_str = tostring(earliest)

To truncate a datetime to a specific boundary before converting it, combine a startof* function with tostring(). For example, to display only the date portion:

['sample-http-logs']
| summarize earliest = min(_time)
| extend date_only = tostring(startofday(earliest))

To extract individual components such as year, month, or day, use datetime_part, getyear, getmonth, or dayofmonth.