MySQL的2個常用函數unix_timestamp()與from_unixtime PostgreSQL并不提供，但通過PostgreSQL強大的擴展性可以輕松的解決問題。
話說遠在天邊，盡在眼前，文檔看仔細，問題迎仞解。PostgreSQL 題供extract與date_part取epoch即可
即
unix_timestamp() = round(date_part('epoch',now()))
from_unixtime(int) = to_timestamp(int)
添加函數unix_timestamp()
CREATE FUNCTION unix_timestamp() RETURNS integer AS $$
SELECT (date_part('epoch',now()))::integer;
$$ LANGUAGE SQL IMMUTABLE;
添加函數from_unixtime()
CREATE FUNCTION from_unixtime(int) RETURNS timestamp AS $$
SELECT to_timestamp($1)::timestamp;
$$ LANGUAGE SQL IMMUTABLE;