update_time
CREATE PROCEDURE update_time(IN input_user_id INT )
BEGIN
DECLARE seconds_since_last INT; START TRANSACTION; SELECT TIMESTAMPDIFF(SECOND, lasttime, NOW()) INTO seconds_since_last FROM user WHERE user_id = input_user_id FOR UPDATE ; UPDATE user SET lasttime = NOW() WHERE user_id = input_user_id ; SELECT seconds_since_last; COMMIT;END