Sql server SQL Server：如何按国家/地区获取前5名订单的总和

这是我第一次来这里：p

我有SQL Server练习

根据Northwind客户居住的国家/地区，按国家/地区显示5个最高采购订单的总和。结果应分为两列：国家、金额

我试过：

SELECT 
    vt.ShipCountry, vt.suma
FROM
    (SELECT 
         o.ShipCountry,
         SUM( UnitPrice * Quantity * (1-discount)) as suma,
         RANK() OVER (PARTITION BY SUM(UnitPrice * Quantity * (1-discount)) ORDER BY shipCountry DESC) AS Rank
     FROM 
         orders o 
     JOIN 
         [Order Details] od ON o.OrderID = od.OrderID
     GROUP BY 
         o.ShipCountry) as vt
WHERE 
    Rank <= 5
GROUP BY 
    vt.ShipCOUNTRY, vt.suma

但是，它检索每个国家所有订单的总和，每个国家只需要前5名

这是另一个问题，同样的问题

SELECT 
    ShipCountry, rk, amount
FROM 
    (SELECT  
         o.ShipCountry, 
         SUM(UnitPrice * Quantity * (1-discount)) amount,
         DENSE_RANK() OVER(PARTITION BY o.ShipCountry ORDER BY SUM(UnitPrice * Quantity * (1-discount)) DESC) AS rk
     FROM 
         Orders o 
     JOIN
         [Order Details] od ON o.OrderID = od.OrderID
      GROUP BY 
         o.shipCountry) AS L
 WHERE 
     rk <= 5;

这两个查询具有相同的行为

请尝试以下操作：

-- first, sum up the total amount of each order
;WITH OrderDetails AS
(
    SELECT 
        o.OrderID,
        TotalOrderAmount = SUM(UnitPrice * Quantity * (1 - discount))
    FROM 
         orders o 
    INNER JOIN 
         [Order Details] od ON o.OrderID = od.OrderID
    GROUP BY
        o.OrderID
),
-- secondly, join the "ShipCountry" to the order totals,
-- and define a ROW_NUMBER() for each country, based on 
-- total order amount
OrderPerCountry AS
(
    SELECT
        o.ShipCountry,
        od.TotalOrderAmount,
        RowNum = ROW_NUMBER() OVER(PARTITION BY o.ShipCountry ORDER BY od.TotalOrderAmount DESC) 
    FROM 
        OrderDetails od 
    INNER JOIN
        dbo.Orders o ON o.OrderID = od.OrderID
)
SELECT * 
FROM OrderPerCountry
WHERE RowNum <= 5

这应该对你有好处-我希望

试试这个：

-- first, sum up the total amount of each order
;WITH OrderDetails AS
(
    SELECT 
        o.OrderID,
        TotalOrderAmount = SUM(UnitPrice * Quantity * (1 - discount))
    FROM 
         orders o 
    INNER JOIN 
         [Order Details] od ON o.OrderID = od.OrderID
    GROUP BY
        o.OrderID
),
-- secondly, join the "ShipCountry" to the order totals,
-- and define a ROW_NUMBER() for each country, based on 
-- total order amount
OrderPerCountry AS
(
    SELECT
        o.ShipCountry,
        od.TotalOrderAmount,
        RowNum = ROW_NUMBER() OVER(PARTITION BY o.ShipCountry ORDER BY od.TotalOrderAmount DESC) 
    FROM 
        OrderDetails od 
    INNER JOIN
        dbo.Orders o ON o.OrderID = od.OrderID
)
SELECT * 
FROM OrderPerCountry
WHERE RowNum <= 5

这应该对你有好处-我希望