MySql-保持最小行数的触发器 [英] MySql - trigger for keeping min number of rows

问题描述

如果要删除的语句的行数少于2000，我想撤消该操作:

I want to undo a delete statement if it brings the number of rows below 2000:

CREATE TRIGGER Trig1
AFTER DELETE ON Tab1

FOR EACH ROW
IF (SELECT COUNT(*) FROM Table1) < 2000
   BEGIN
      INSERT INTO Table1 (select * from old);
   END;
END IF;

但是它不起作用.有人可以告诉我我在做什么错，应该怎么看?

But it is not working. Can someone tell me what am I doing wrong, and how this should look?

推荐答案

尝试，

INSERT INTO Table1
SELECT * 
FROM   old

记住点

• 由于您使用的是 *
，因此两个表上的表数和数据类型必须匹配

• the number of tables and data types must match on both tables since you are using *

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