如何在交叉引用另一個表時更新記錄？

Question

道歉如果標題沒有準確地描述問題（它可能沒有）。我有以下兩個表： -

tLiveTable：

PieceID  LocationRef 
------------------------ 
100    5 

tPieceTable：

ID BatchNo  PieceNumber 
------------------------------ 
50 ABC   X1 
100 ABC   X1 

我怎樣才能更新LocationRef那塊在tLiveTable只給出BatchNo和PieceNo？

我已嘗試以下步驟：在tPieceTable

UPDATE tLiveTable 
SET LocationRef = 'blabla unimportant' 
WHERE 
PieceID = (SELECT ID FROM tPieceTable WHERE (BatchNo = 'ABC') AND (PieceNo = 'X1')) 

但可以有多個條目具有相同BatchNo和PieceNo。我只想從tPieceTable中檢索ID，它的ID現在是tLiveTable中的ID。

我真的應該使用INNER JOIN嗎？

Answer 1

您的查詢將不工作爲SELECT ID FROM tPieceTable WHERE (BatchNo = 'ABC') AND (PieceNo = 'X1')返回多個ID

試試這個;

UPDATE L SET LocationRef = 'blabla unimportant' 
FROM tLiveTable L JOIN tPieceTable P 
    ON L.PieceID = P.ID 
WHERE (P.BatchNo = 'ABC') AND (P.PieceNo = 'X1') 

或者使用IN爲=

UPDATE tLiveTable 
SET LocationRef = 'blabla unimportant' 
WHERE 
PieceID IN (SELECT ID FROM tPieceTable WHERE (BatchNo = 'ABC') AND (PieceNo = 'X1'))