关于数据库触发器问题，快来看看啊。。。

delimiter //
CREATE DEFINER=`root`@`localhost` TRIGGER `up_member_count` AFTER UPDATE ON `pre_common_member_count`
FOR EACH ROW
begin
set @d1=NEW.extcredits4
set @d2=OLD.extcredits4
set @id=OLD.uid
set @d3=@d2-@d1
if @d3>0 then
update tf_users set tf_users.pay_points=pay_points+@d3 where user_id=@id
end if
end
//
delimiter ;