Sql存储过程中的两列相乘

Question

我有一张带

的桌子

StockID   ItemID   Quantity   Price

现在我想选择类似这样的数据

StockID   ItemID   Quantity Price   TotalPrice(Quantity*Price)

我试过了

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

但它给了我错误Subquery returned more than 1 value.

请帮我解决这个问题

Answer 1

不需要做子查询就可以得到两列的乘积，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