Datetime Functions

function current_datetime() returns datetime
function current_datetime(string) returns datetime

function datetime(bigint, bigint, bigint, bigint, bigint, bigint) returns datetime
function datetime(date) returns datetime
function datetime(date, time) returns datetime
function datetime(timestamp) returns datetime
function datetime(timestamp, string) returns datetime

function datetime_add $1($1, interval) returns $1
	where $1 in (datetime, timestamp)

function datetime_diff $1($1, $1, part string) returns bigint
	where part in (microsecond, millisecond, second, minute, hour, day, week, week(monday), week(tuesday), week(wednesday), week(thursday), week(friday), week(saturday), week(sunday), isoweek, month, quarter, year, isoyear)
	where $1 in (datetime, timestamp)

function datetime_sub $1($1, interval) returns $1
	where $1 in (datetime, timestamp)

function datetime_trunc $1($1, date_time_part string) returns $1
	where date_time_part in (microsecond, millisecond, second, minute, hour, day, week, week(monday), week(tuesday), week(wednesday), week(thursday), week(friday), week(saturday), week(sunday), isoweek, month, quarter, year, isoyear)
	where $1 in (datetime, timestamp)

function format_datetime $1(string, $1) returns string
	where $1 in (datetime, timestamp)

function parse_datetime(string, string) returns datetime