timestamp calculations - Mailing list pgsql-general

Hello,

I'm converting a mysql db to postgres and ran into this line of code:

   $SQL = "select username from users where user_id = ? AND session = ?
           AND ADDDATE(last_login, INTERVAL 30 MINUTE)>CURRENT_TIMESTAMP()

How do I implement adddate to get this kind of funcionality?

Thanks,

Steve Leibel