date_trunc()

date_trunc

date_trunc는

date_trunc(field, source [, time_zone ])

field는 timestamp, timestamp with time znoe, interval 을 사용할 수 있고

source는
microseconds, milliseconds, second, minute, hour, day, week, month, quarter, year, decade, century, millennium를 사용할 수 있다

Example

SELECT date_trunc('hour', TIMESTAMP '2001-02-16 20:38:40');
_Result:_ `2001-02-16 20:00:00`

SELECT date_trunc('year', TIMESTAMP '2001-02-16 20:38:40');
_Result:_ `2001-01-01 00:00:00`

SELECT date_trunc('day', TIMESTAMP WITH TIME ZONE '2001-02-16 20:38:40+00');
_Result:_ `2001-02-16 00:00:00-05`

SELECT date_trunc('day', TIMESTAMP WITH TIME ZONE '2001-02-16 20:38:40+00', 'Australia/Sydney');
_Result:_ `2001-02-16 08:00:00-05`

SELECT date_trunc('hour', INTERVAL '3 days 02:47:33');
_Result:_ `3 days 02:00:00`