在SQL存儲過程中將兩列相乘

Question

我有一張桌子

StockID   ItemID   Quantity   Price

現在我想選擇這樣的數據

StockID   ItemID   Quantity Price   TotalPrice(Quantity*Price)

我嘗試了這個

ALTER PROC [dbo].[SelectItemStock] 
@Item   int
as
BEGIN
    SELECT  Stock.*, (SELECT Quantity*Price FROM Stock) AS TotalPrice
    FROM    Stock
    WHERE   ItemID = @Item
END

但這給了我錯誤， Subquery returned more than 1 value.

請幫我解決這個問題

Answer 1

您無需執行子查詢即可獲得兩列的乘積，只需將其直接相乘即可，

ALTER PROC [dbo].[SelectItemStock] 
@Item   int
as
BEGIN
    SELECT  Stock.*, 
            (Quantity*Price) AS TotalPrice
    FROM    Stock
    WHERE   ItemID = @Item
END