编写一个子查询,返回订单数最多的客户下的订单总数。包括 customerid 和下订单的数量。
USE Northwind
GO
SELECT CustomerID,
COUNT(Orders.OrderID) AS TotalOrders,
SUM(OrderAmounts.DollarAmount) AS TotalDollarAmount
FROM [Orders]
Left Outer JOIN (SELECT OrderID, Sum(Quantity*SalePrice) AS DollarAmount
FROM OrderItems GROUP BY OrderID) AS OrderAmounts
ON Orders.OrderID = OrderAmounts.OrderID
GROUP BY CustomerID
ORDER BY Count(Orders.OrderID) DESC
我收到此响应:Msg 208,Level 16,State 1,Line 1 无效的对象名称“OrderItems”。
???