% This is generated by ESQL's AbstractFunctionTestCase. Do not edit it. See ../README.md for how to regenerate it.

**Parameters**

`datePart`
:   Part of the date to extract.  Can be: `aligned_day_of_week_in_month`, `aligned_day_of_week_in_year`, `aligned_week_of_month`, `aligned_week_of_year`, `ampm_of_day`, `clock_hour_of_ampm`, `clock_hour_of_day`, `day_of_month`, `day_of_week`, `day_of_year`, `epoch_day`, `era`, `hour_of_ampm`, `hour_of_day`, `instant_seconds`, `micro_of_day`, `micro_of_second`, `milli_of_day`, `milli_of_second`, `minute_of_day`, `minute_of_hour`, `month_of_year`, `nano_of_day`, `nano_of_second`, `offset_seconds`, `proleptic_month`, `second_of_day`, `second_of_minute`, `year`, or `year_of_era`. Refer to [java.time.temporal.ChronoField](https://docs.oracle.com/javase/8/docs/api/java/time/temporal/ChronoField.html) for a description of these values.  If `null`, the function returns `null`.

`date`
:   Date expression. If `null`, the function returns `null`.

