從子查詢中更新多行

Question

我試圖從子查詢更新多行。請注意，ID是表中的主鍵。

這裏是我的查詢：

SELECT tm.ID, tm.LocID = (SELECT CASE COUNT(*) WHEN 1 THEN MAX(LocID) END 
       FROM tblLoc tl 
       WHERE tl.LocID = tm.LodID) 
FROM tblMain tm 

這裏是我的更新語句：

Update tblMain 
set LocID = TMP.LocID 
(
    SELECT tm.ID, tm.LocID = (SELECT CASE COUNT(*) WHEN 1 THEN MAX(LocID) END 
       FROM tblLoc tl 
       WHERE tl.LocID = tm.LodID) 
    FROM tblMain tm 

) AS TMP 
where tblMain.ID = TMP.ID 

我得到不正確的語法。

Answer 1

Update tblMain 
set LocID = TMP.LocID 
FROM tblMain INNER JOIN 
(
    SELECT tm.ID, tm.LocID = (SELECT CASE COUNT(*) WHEN 1 THEN MAX(LocID) END 
       FROM tblLoc tl 
       WHERE tl.LocID = tm.LodID) 
    FROM tblMain tm 

) AS TMP 
ON tblMain.ID = TMP.ID