MySql从另一个减去一个表 [英] MySql Subtract a table from another

问题描述

我有两个表:A包含所有数据，表B由A随机选择其数据的％25创建.因此，A和B具有完全相同的列.也没有唯一的列.

I have two tables: A contains all the data, table B created from A selecting %25 of its data randomly. So A and B have exact same columns. Also there is no unique column.

我要做的是从A中减去B.有什么想法吗?

What I want to do is subtract B from A. Any ideas?

推荐答案

要查看A中的所有行，但B中的行除外:

To view all rows in A except those in B:

SELECT * FROM A
WHERE (field1, field2, ..., fieldN) NOT IN
( SELECT *
  FROM B
) ;

要从表A中实际删除B中的行:

To actually delete from table A the rows that are in B:

DELETE FROM A
WHERE (field1, field2, ..., fieldN) IN
( SELECT *
  FROM B
) ;

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