-1
上使用子查询我试图为每个客户返回CustomerID,CompanyName,OrderID和小计以订购小于客户平均小计金额的小计金额。这些是我正在使用的表格和下面的查询。我不确定我返回的价值是否正确,并且希望有人能够帮助我了解他们是否基于我的查询。提前致谢。MySQL - 在加入和
Orders
Columns
OrderID
CustomerID
EmployeeID
OrderDate
RequiredDate
OrderDetails
Columns
OrderID
ProductID
UnitPrice
Quantity
Products
Columns
ProductID
ProductName
QuantityPerUnit
UnitPrice
Customers
Columns
CustomerID
CompanyName
ContactName
Country
SELECT A.CustomerID, A.CompanyName, A.Subtotal, A.OrderID, AVGSubtotal
FROM (
SELECT
C.CustomerID,
C.CompanyName,
(D.UnitPrice * P.QuantityPerUnit) AS Subtotal,
D.OrderID
FROM Customers C
JOIN Orders O ON C.CustomerID = O.CustomerID
JOIN OrderDetails D ON D.OrderID = O.OrderID
JOIN Products P ON P.ProductID = D.ProductID
GROUP BY
D.OrderID, C.CustomerID
) A
JOIN (
SELECT
S.CustomerID, S.CompanyName, AVG(S.Subtotal) as AVGSubtotal
FROM (
SELECT
C.CustomerID,
C.CompanyName,
(D.UnitPrice * P.QuantityPerUnit) AS Subtotal
FROM Customers C
JOIN Orders O ON C.CustomerID = O.CustomerID
JOIN OrderDetails D ON D.OrderID = O.OrderID
JOIN Products P ON P.ProductID = D.ProductID
GROUP BY
D.OrderID, C.CustomerID
) S
GROUP BY
S.CustomerID
) B ON A.CustomerID = B.CustomerID
WHERE
A.CustomerID = B.CustomerID AND
A.Subtotal > B.AVGSubtotal
ORDER BY
A.CustomerID, A.CompanyName
;
你想要一些为 “检查代码”?如果没有错误/失败,那么问答不适合您的帖子。 – mickmackusa