mysql查询问题

Question

问题描述

有一张客户表A和订单表B 订单表和客户表的客户ID关联
客户半年不做订单或着没做过订单就是休眠状态，客户没做过订单，那么订单表里就没有和这个客户相关的数据

现在怎么用一条sql语句就可以查出从来没做订单，和半年没做过订单的客户id

Answer 1

好几种写法，简单写了下，你做个参考吧

从来没做订单：
select a.id,count(b.user_id) count from A a left join B b on b.user_id = a.id group by a.id HAVING count = 0;

半年没做过订单：
select a.id,IFNULL(b.create_time,0) time from A a left join (select * from B order by create_time desc) b on b.user_id = a.id group by a.id HAVING time < unix_timestamp(date_sub(now(),interval 6 month));