更新Sql計算語句

Question

我可以知道如何更新Sql Calculation語句嗎？

例如我想更新的總和tatal表

下面是代碼

SELECT p.Qty AS pQty, 
     SUM(t.Qty) AS tQty, 
     p.Qty - SUM(t.Qty) AS total , 
     p.PName 
FROM tblTempTransaction t , 
    tblProducts p 
WHERE t.UserID= 2 
    AND t.OrderID=1 
    AND p.pid = t.pid 
GROUP BY t.UserID, 
     p.qty , 
     p.PName , 
     t.OrderID 

UPDATE tblProducts 
SET qty = p.Qty - SUM(t.Qty) 
WHERE t.UserID= 2 
    AND t.OrderID=1 
    AND p.pid = t.pid 
GROUP BY t.UserID, 
     p.qty , 
     p.PName , 
     t.OrderID 

我會得到一套數量= p.Qty錯誤 - SUM（t.Qty）

我可以知道如何解決這個問題嗎？ 謝謝。

Answer 1

假設您選擇的查詢是正確的..你忘了 '從'

UPDATE tblProducts 
    SET qty = p.Qty - sq.total from (select SUM(t.Qty) as total from "table" as t 
    WHERE t.UserID= 2 and t.OrderID=1 and p.pid = t.pid 
GROUP BY t.UserID, p.qty ,p.PName ,t.OrderID) as sq