Спасибоlevantuev,
Код:SELECT u.user_id, u.username, COUNT(tor.topic_id) as releases FROM bb_users u LEFT outer JOIN bb_bt_torrents tor ON ( tor.poster_id = u.user_id ) LEFT outer JOIN bb_bt_users bt ON ( bt.user_id = u.user_id ) WHERE u.user_active = 1 AND tor.reg_time > UNIX_TIMESTAMP() - 30*24*60*60 GROUP BY u.user_id ORDER BY releases DESC