mysql中not in子查询不能为空

转载自：https://blog.csdn.net/headingalong/article/details/77744755

 

错误sql

 

delete from company_info where id NOT in (SELECT company_info_ID FROM USER);

因为null的原因，导致出现子查询的结果为空。

正确的写法是

 

-- 清除重复的不可用的公司信息 delete from company_info where id NOT in (SELECT company_info_ID FROM USER where company_info_ID is not null);