Gets the hour (24-hour clock) of a timestamp field.

asstringfalse_hourThe name of the output field.
fieldstringfalse@timestampThe name of the input field. [a]
timezonestringfalse The time offset to use e.g., -01:00. If not specified, the query’s offset will be used.
timezoneFieldstringfalse@timezoneThe name of the field containing the timezone to use, if not specified the query's timezone will be used. This is ignored if the timezone parameter is passed as well. If this is not defined the timezone offset of the query will be used.

[a] When you provide only one parameter, the implied parameter is field