mysql中not in子查詢不能為空

轉載自：https://blog.csdn.net/headingalong/article/details/77744755

 

錯誤sql

 

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

因為null的原因，導致出現子查詢的結果為空。

正確的寫法是

 

-- 清除重復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);