MySQL 触发器和错误代码 1362

Question

所以我对触发器有以下查询：

DELIMITER $$
CREATE TRIGGER user_log_update BEFORE UPDATE on user_log
FOR EACH ROW
BEGIN
insert into user_log
(id, user_id, name, username, password, email, user_type_id, created)
VALUES(OLD.id, OLD.user_id, OLD.name, OLD.username, OLD.password, OLD.email, OLD.user_type_id, OLD.created);
IF (OLD.id = 1) THEN
SET OLD.id = OLD.id +1;
END IF;
SELECT * FROM user_log;
END$$
DELIMITER ;

当我尝试执行这部分脚本时，我得到Error Code: 1362. Updating of OLD row is not allowed in trigger

我不知道为什么会出现这个错误，我也没有发现语法有任何问题。

有人知道怎么解决吗？

Answer 1

所以，改为增加new：

DELIMITER $$
CREATE TRIGGER user_log_update BEFORE UPDATE on user_log
FOR EACH ROW
BEGIN
    insert into user_log(id, user_id, name, username, password, email, user_type_id, created)
        VALUES(OLD.id, OLD.user_id, OLD.name, OLD.username, OLD.password, OLD.email, OLD.user_type_id, OLD.created);
    IF (OLD.id = 1) THEN
        SET NEW.id = OLD.id +1;
    END IF;
END$$
DELIMITER ;

Answer 2

 delimiter |
create trigger display_student_table 
        before insert on student_table
        for each row

Begin
    set new.student_name=trim(new.student_name);
    set new.branch=trim(new.branch);
    set new.address=trim(address);
End ;

|
    delimiter ;