在另一个表中的多个（涉及另一个表）行记录

Question

我有两个表tblOrder和tblOrderDetail表。

tblOrderDetail包含以下行：

OrderDetailID OrderID Product Quantity UnitPrice Discount Total 

    1   1  ABC  10  $240.00  10  $2,160.00 
    2   2  CDF  100  $200.00  10  $18,000.00 
    3   3  GHI  200  $150.00  0  $30,000.00 
    4   1  XYZ  40  $100.00  5  $3,800.00 

我想SQL查询来获得tblOrder，这是和小计列涉及的OrderID共有来自tblOrderDetail这样的：

OrderID  Sub Total 
    1   $5,960.00 
    2   $18,000.00 
    3   $30,000.00 

我尝试这条sql查询：

SELECT 
    OrderID 
    ,(
     SELECT 
      SUM(((tblOrderDetail.UnitPrice) - (tblOrderDetail.UnitPrice * (tblOrderDetail.Discount/100))) * (tblOrderDetail.Quantity)) 
     FROM 
      tblOrderDetail 
     WHERE tblOrderDetail.OrderID = tblOrder.OrderID 
    ) AS [Sub Total] 
FROM 
    tblOrder 

但它给了这个

OrderID  Sub Total 
    1   $0.00 
    2   $0.00 
    3   $0.00 

请注意我希望Sub Total列动态不是通过tblOrderDetail表中Total Column的总和。

我希望有人能理解我在说什么，并希望能帮助我实现这一点！

Answer 1

使用GROUP BY子句与SUM聚合函数，

Select *, sum(Total) as totalforOrder from ordertbl group by OrderID; 

演示SQLFiddle

按你的问题，这里是一个相关查询

SELECT 
tblOrder.OrderID 
,(
    SELECT 
     SUM(((tblOrderDetail.UnitPrice) - (tblOrderDetail.UnitPrice * (tblOrderDetail.Discount/100))) * (tblOrderDetail.Quantity)) 
    FROM 
     tblOrderDetail 
    WHERE tblOrderDetail.OrderID = tblOrder.OrderID 
) AS SubTotal 

FROM tblOrder;

其工作罚款SQLFiddle

Answer 2

您可以使用组通过你为什么用公式来做到这一点

Select OrderID, sum(Total) as [Sub Total] from tblOrderDetail group by OrderID; 

You can get more details here !