sql - サブクエリ列を外部順序で参照することはできません

Question

以下のORDER BY句が原因でエラーが発生しています。ORDER BY節で TotalPrice 列を参照するにはどうすればよいですか:

SELECT * FROM
(

SELECT O.OrderID,
       (SELECT SUM(SubTotal) FROM DB_OrderDetails OD WHERE OD.OrderID = O.OrderID) AS TotalPrice,
       ROW_NUMBER() OVER (ORDER BY TotalPrice) AS RowNum

    FROM DB_Orders O

) Orders

Answer 1

同じサブクエリで名前で参照することはできません。外側のクエリでそれを行う必要があります。

SELECT orders.*, 
       ROW_NUMBER() OVER (ORDER BY TotalPrice) AS RowNum FROM
(
    SELECT O.OrderID,
       (SELECT SUM(SubTotal) FROM DB_OrderDetails OD 
        WHERE OD.OrderID = O.OrderID) AS TotalPrice
    FROM DB_Orders O
) Orders

Answer 2

これはどう：

select 
    o.orderID,
    sum(od.SubTotal) as TotalPrice,
    row_number() over (order by sum(od.SubTotal)) as RowNum
from DB_Orders o
join DB_OrderDetails od
    on o.OrderID = od.OrderID
group by o.OrderID

以下に例を示します: SQL Fiddle