UNIX_TIMESTAMP function does not exist in PostgreSQL

[nobody]

fixed by adding the following functions I found at
http://www.postgresql.org/docs/7.4/interactive/functions-datetime.html:
CREATE OR REPLACE FUNCTION UNIX_TIMESTAMP(TIMESTAMP
WITHOUT TIME ZONE)
RETURNS BIGINT
LANGUAGE SQL
IMMUTABLE STRICT
AS 'SELECT EXTRACT(EPOCH FROM $1)::bigint;';

CREATE OR REPLACE FUNCTION UNIX_TIMESTAMP(TIMESTAMP
WITH TIME ZONE)
RETURNS BIGINT
LANGUAGE SQL
IMMUTABLE STRICT
AS 'SELECT EXTRACT(EPOCH FROM $1)::bigint;';