MySQL插入其他刪除存儲過程

Question

我目前正在開發一個切換系統，允許用戶將項目添加到集合中。然後他們可以刪除從數據庫中刪除該行的項目。這很容易使用2個查詢來完成，但我想用存儲過程替換它，以便不必使用2個查詢來完成此操作。我想要做的是檢查一行是否存在，如果它刪除它，如果沒有插入它。

我正在使用phpmyadmin，我正在嘗試創建一個例程。我已經添加了被設置爲「IN」

IF (SELECT 1 = 1 FROM useritems WHERE ItemID = itemid AND UserID = userid) THEN 
    BEGIN 
     DELETE FROM useritems WHERE ItemID = itemid AND UserID = userid 
    END; 
ELSE 
    BEGIN 
     INSERT INTO useritems (ItemID, UserID) VALUES(itemid, userid) 
    END; 
END IF; 

2（itemid的，使用的參數當我嘗試提交它，我得到以下錯誤

MySQL said: #1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'END; 
ELSE 
    BEGIN 
     INSERT INTO useritems (ItemID, UserID) VALUES(ite' at line 4 

Answer 1

這是正確的語法IF聲明MySQL：

IF search_condition THEN statement_list [ELSEIF search_condition THEN statement_list] ... [ELSE statement_list] END IF

參考，以MySQL Dev Site

所以修復你的代碼是這樣的：

IF EXISTS (SELECT 1 FROM useritems WHERE ItemID = itemid AND UserID = userid) THEN 

    DELETE FROM useritems WHERE ItemID = itemid AND UserID = userid; 
ELSE 
    INSERT INTO useritems (ItemID, UserID) VALUES(itemid, userid); 
END IF; 

Answer 2

IF (SELECT * FROM useritems WHERE ItemID = itemid AND UserID = userid) 
THEN 
     DELETE FROM useritems WHERE ItemID = itemid AND UserID = userid 
ELSE 
     INSERT INTO useritems (ItemID, UserID) VALUES(itemid, userid) 
END IF;