MySQL触发器：阻止插入操作，条件判断用户状态

CREATE TRIGGER trigger_name BEFORE INSERT ON bbb FOR EACH ROW BEGIN DECLARE user_status INT; SELECT status INTO user_status FROM aaa WHERE user = NEW.user; IF user_status = 0 THEN SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = 'Insertion aborted. User status is 0.'; END IF; END;