mysql 联表查询

问题描述

A表order_id data 1 1 2 2 3 3B表order_id state 11 22

查找A中与B不重复的对应order_id的data（即order_id=3的data），sql语句怎么写？

问题解答

select data from a where order_id not in ( select distinct order_id from b );回答2：

select datafrom A left join B on A.order_id = B.order_idwhere isnull(B.state)

select * from A where order_id not in (select order_id from B)回答4：

SELECT a.data FROM a LEFT JOIN b ON a.order_id=b.order_id WHERE b.order_id IS NULL回答5：

select data from A where A.id not IN (select B.id from B)

select data from a where not exists (select 1 from b where a.order_id = b.order_id)