用於刪除行的MySQL子查詢

Question

我在執行子查詢時遇到問題，以便刪除我的應用程序中的某些特定行。這是我錯誤的SQL：

delete from player_news_items 
    where id IN 
     (select id from player_news_items 
     where player_id NOT IN (select id from players)); 

什麼是寫這個查詢的正確方法？

Answer 1

在MySQL中，除非使用join，否則不能引用update或delete中正在修改的表。不過，我覺得你可能只是想這樣的：

delete pni 
    from player_news_items pni 
    where player_id NOT IN (select id from players)); 

作爲一個說明，我會建議寫這與not exists：

delete pni 
    from player_news_items pni 
    where not exists (select 1 from players p where p.player_id = pni.player_id);