删除联接中不存在的记录 [英] Delete records not present in join

问题描述

想象两个表格（A和B）：

Imagine two tables (A and B):

A        B
1        2
2        3 
6        5 
4        7
9        11
         13
         23
         9 

现在我要删除A中不存在的记录，例如从A删除1，6和4.

Now I want to delete records from A that are not present in B, e.g deleting 1, 6 and 4 from A.

我最初的想法是，你可以否定连接的结果。

My initial idea is that you could 'negate' the results of a join.

推荐答案

DELETE FROM A WHERE NOT EXISTS (SELECT * FROM B WHERE A.id = B.id)

我假设这些列被命名为 id 。

I've assumed that those columns are named id.

这篇关于删除联接中不存在的记录的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！