在mySQL中刪除具有多個產品記錄的用戶

Question

有一個名爲user_products的表，其中包含用戶已授權的每個產品的記錄。

USER_ID，PRODUCT_ID，（其它一些領域，如時間戳）

我有18個產品，但要找到具有產品3的紀錄，併爲產品4記錄所有用戶，然後刪除記錄中他們對產品3

Answer 1

DELETE 
FROM user_products AS up3 
WHERE product_id = 3 
    AND EXISTS 
     (SELECT * 
     FROM user_products AS up4 
     WHERE up4.product_id = 4 
      AND up4.user_id = up3.user_id 
    ) 

或JOIN：

DELETE up3 
FROM user_products AS up3 
    JOIN user_products AS up4 
    ON up4.user_id = up3.user_id 
WHERE up3.product_id = 3 
    AND up4.product_id = 4