SQL合併更新特定屬性

Question

我是SQL新手，我想用來自臨時小數據庫的數據更新「大」數據庫。

CREATE PROCEDURE sp_update_DimSomeone 
AS 
BEGIN 
MERGE DimSomeone AS V 
USING DimSomeone_temp AS T 
    ON V.AltKey = T.Altkey 
WHEN NOT MATCHED BY TARGET AND T.AltKey <> '' THEN 
    INSERT VALUES (AltKey, Param1, Param2, Param3) 
WHEN MATCHED AND T.Param1 <> V.Param1 THEN 
    UPDATE SET V.Param1 = T.Param1 
WHEN MATCHED AND T.Param2 <> V.Param2 THEN 
    UPDATE SET V.Param2 = T.Param2 
WHEN MATCHED AND T.Param3 <> V.Param3 THEN 
    UPDATE SET V.Param3 = T.Param3 

END 

我已經得到了錯誤：類型的行動「WHEN MATCHED」不能出現不止一次在MERGE語句的「更新」的條款。

我明白這個消息，但我不想更新整行，只有屬性，這是不一樣的。 （例如，帶有AltKey 001的客戶在temp中更改您的地址，我想只更新Param3（例如地址），而不是整行）。

感謝您的回答！

Answer 1

爲什麼不總是更新param1，param2和param3？結果將是一樣的！

CREATE PROCEDURE sp_update_DimSomeone 
AS 
BEGIN 
MERGE DimSomeone AS V 
USING DimSomeone_temp AS T 
    ON V.AltKey = T.Altkey 
WHEN NOT MATCHED BY TARGET AND T.AltKey <> '' THEN 
    INSERT VALUES (AltKey, Param1, Param2, Param3) 
WHEN MATCHED THEN 
    UPDATE SET V.Param1 = T.Param1, 
       V.Param2 = T.Param2, 
       V.Param3 = T.Param3 
END 

編輯： 你至少可以檢查，如果有這3列已經改變，所以你會跳過完全一致行：

CREATE PROCEDURE sp_update_DimSomeone 
AS 
BEGIN 
MERGE DimSomeone AS V 
USING DimSomeone_temp AS T 
    ON V.AltKey = T.Altkey 
WHEN NOT MATCHED BY TARGET AND T.AltKey <> '' THEN 
    INSERT VALUES (AltKey, Param1, Param2, Param3) 
WHEN MATCHED AND (T.Param1 <> V.Param1 OR T.Param2 <> V.Param2 OR T.Param3 <> V.Param3) THEN 
    UPDATE SET V.Param1 = T.Param1, 
       V.Param2 = T.Param2, 
       V.Param3 = T.Param3 
END