用mysql写一个判断如果 子查询 user=NEWuser 所在行的 status = 0 就继续执行否则就抛出异常

DELIMITER $$ CREATE TRIGGER check_status BEFORE INSERT ON your_table FOR EACH ROW BEGIN DECLARE status_value INT;

SELECT status INTO status_value FROM your_table WHERE user = NEW.user;

IF status_value = 0 THEN
    -- 继续执行
ELSE
    SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = 'User status is not 0.';
END IF;

END$$ DELIMITER ;