Examples:
Code: Select all
dbadmin=> \x
Expanded display is on.
dbadmin=> select sysdate,
dbadmin-> date_trunc('year', sysdate) trunc_year,
dbadmin-> date_trunc('month', sysdate) trunc_month,
dbadmin-> date_trunc('week', sysdate) trunc_week,
dbadmin-> date_trunc('day', sysdate) trunc_day,
dbadmin-> date_trunc('hour', sysdate) trunc_hour,
dbadmin-> date_trunc('minute', sysdate) trunc_minute,
dbadmin-> date_trunc('second', sysdate) trunc_second;
-[ RECORD 1 ]+--------------------------
sysdate | 2012-07-03 11:46:23.38257
trunc_year | 2012-01-01 00:00:00
trunc_month | 2012-07-01 00:00:00
trunc_week | 2012-07-02 00:00:00
trunc_day | 2012-07-03 00:00:00
trunc_hour | 2012-07-03 11:00:00
trunc_minute | 2012-07-03 11:46:00
trunc_second | 2012-07-03 11:46:23
dbadmin=> select date_trunc('year', sysdate) - 1 last_day_of_last_year;
last_day_of_last_year
-----------------------
2011-12-31 00:00:00
(1 row)
Code: Select all
dbadmin=> select sysdate,
dbadmin-> date_part('century', sysdate) current_century,
dbadmin-> date_trunc('century', sysdate) first_date_of_the_current_century;
sysdate | current_century | first_date_of_the_current_century
---------------------------+-----------------+-----------------------------------
2012-07-03 14:22:07.99621 | 21 | 2001-01-01 00:00:00