在更新时创建触发器以将旧值插入到MYSQL中的其他表中

我有两张桌子.第一个是我的person表,它有id,name,creation_date作为值,我有一个old_person表(id,name,modified_date),我想在实际更改之前填充person的值.我该怎么办呢？我尝试过触发但失败了.

我尝试如下

create trigger Person_Trigger Update on person
before update
as
insert into old_person(id, name, modified) 
select id, new.name, getdate()
from person

它给了我语法错误…也没有很多触发器引用,一点推动将非常感激！

解决方法:

看看下面的例子

SQL Fiddle DEMO

我自己也有点麻烦,但从How to Create Triggers in MySQL开始就有一条线让我思考

The first MySQL command we’ll issue is a little unusual:

DELIMITER $$

Our trigger body requires a number of SQL commands separated by a
semi-colon (;). To create the full trigger code we must change
delimiter to something else — such as $$.

Finally, we set the delimiter back to a semi-colon:

DELIMITER ;

因此,在SQL Fiddle中,我将查询终止符更改为GO,这似乎是最重要的工作.

CREATE TABLE person
(
  id INT,
  name varchar(20)
)
GO
CREATE TABLE old_person
(
  id INT,
  name varchar(20),
  modified DATETIME
)
GO
CREATE TRIGGER Person_Trigger before update on person
FOR EACH ROW BEGIN
  INSERT INTO old_person(id, name, modified) 
  VALUES (OLD.id, OLD.name, NOW());
END
GO



INSERT INTO person VALUES (1,'TADA')
GO

UPDATE person SET name = 'FOO'
GO

标签：mysql,sql,sql-update,triggers,sql-insert
来源： https://codeday.me/bug/20190629/1323866.html