Question

我需要两个表来创建查询。我相信我也需要加入他们。

我需要从CustomerName表中获取客户的Address和Customer，但我还需要查询以显示客户下达的所有订单的总金额。因此，如果客户今年总共花费了300美元，那么300美元就是我想要实现的产出。

我有一个名为Order Details的表，其使用的OrderID与CustomerID绑定，unitprice和quantity列位于Order Details 1}}表。我正在试图弄清楚如何复制这些但我会发疯。

我试过这个以至少从订单中得到总数，但我确实有语法错误：

SELECT unitprice, 
       quantity 
FROM   [Order details] (unitprice * quantity) AS Totalorders, 
       from [Order Details] 
WHERE  orderid > 0

这也没有运气：

SELECT customers.companyname                                AS 'Company Name', 
       customers.address                                    AS 'Address', 
       [order details].unitprice * [order details].quantity AS 'Orders' 
FROM   customers 
       LEFT JOIN orders 
              ON customers.customerid = orders.customerid 
ORDER  BY customers.companyname, 
          customers.address, 
          orders

由于

Answer 1

如果它是一对多的关系，您的查询将类似于：

SELECT
Customers.CompanyName AS 'Company Name',
Customers.Address AS 'Address',
SUM(O.Unitprice * O.quantity) as 'Orders'
FROM Customers
LEFT JOIN [Order Details] O
ON Customers.CustomerID = O.CustomerID
GROUP BY Customers.CompanyName, Customers.Address
ORDER BY Customers.CompanyName, Customers.Address

Answer 2

您需要加入订单详细信息并通过汇总进行分组：

SELECT c.CompanyName AS "Company Name",
       c.Address AS "Address",
       sum(od.Unitprice * od.quantity) as "Orders"
FROM Customers c LEFT JOIN
     Orders o
     ON c.CustomerID = o.CustomerID left join
     [Order Details] od
     on od.orderid = o.orderid
GROUP BY c.CompanyName, c.Address
ORDER BY c.CompanyName, c.Address

此外，我做了一些风格上的改变。我在表名中添加了别名。我发现阅读c.CompanyName而不是Customers.CompanyName要容易得多。我更改了列别名上的分隔符以使用双引号而不是单引号。我将单引号与语句中的字符串常量相关联。

SQL Server查询每个customerID的订单总金额

2 个答案: