Unix timestamp in PostgreSQL

Since I’m looking for it every time, I’ve decided to put it here.

To convert UNIX Timestamp to Postgres timestamp:

SELECT TIMESTAMP WITH TIME ZONE 'epoch' +
    INTERVAL '1 second' * 1252606560 AS postgres_timestamp;

To convert Postgres timestamp to UNIX timestamp:

SELECT extract('epoch' FROM now())::int AS unix_timestamp;

Skip the ::int cast to get fractional part.