Discard millisecond part from timestamp

Question

How can I discard/round the millisecond part, better if the second part is also removed from a timestamp w/o timezone ?

Answer 1

Discard milliseconds:

SELECT DATE_TRUNC('second', CURRENT_TIMESTAMP::timestamp);

2019-08-23 16:42:43

Discard seconds:

SELECT DATE_TRUNC('minute', CURRENT_TIMESTAMP::timestamp);

2019-08-23 16:42:00

Answer 2

A cast to timestamp(0) or timestamptz(0) rounds to full seconds:

SELECT now()::timestamp(0);

Fractions are not stored in table columns of this type.

date_trunc() truncates (leaves seconds unchanged) - which is often what you really want:

SELECT date_trunc('second', now()::timestamp);

Answer 3

if you just want time, here is the code for postgres

SELECT DATE_TRUNC('second', CURRENT_TIMESTAMP::timestamp)::time;

it will return 'time without time zone' data type