Question

我有A，B，C是三个不同的表，我需要删除A表中的记录，这些表在B和C表中都没有退出。

样品：

 delete from A 
 where name NOT IN ( select name from B inner join C);

Answer 1

我喜欢使用左连接来做这样的事情。我首先创建一个这样的select语句：

SELECT  *
FROM    TableA AS a 
        LEFT OUTER JOIN TableB AS b ON a.Name = b.Name
        LEFT OUTER JOIN TableC AS c ON a.Name = c.Name
WHERE  b.Name IS NULL
       AND c.NAME IS NULL

然后我转换为这样的DELETE语句：

DELETE  a 
FROM    TableA AS a 
        LEFT OUTER JOIN TableB AS b ON a.Name = b.Name
        LEFT OUTER JOIN TableC AS c ON a.Name = c.Name
WHERE  b.Name IS NULL
       AND c.NAME IS NULL

如何从表中删除两个不同表中的不相等记录

1 个答案: