Question

我正在使用MS AdventureWorks2012进行教程，我想使用AdventureWorks2012编写一个查询来查找每个客户的平均销售额（换句话说，每个客户的平均销售额）。以下是我的尝试，它没有运行。我在这里做错了什么？

SELECT  soh.CustomerID AS 'Customer ID'
,p.FirstName + ' ' + p.LastName AS 'Customer Name'
,AVG(soh.TotalDue) AS 'Average Sales Amount Per Customer'
FROM  Sales.SalesOrderHeader AS soh
INNER JOIN Sales.Customer AS c ON c.CustomerID = soh.CustomerID
INNER JOIN Person.BusinessEntityContact AS bec ON bec.PersonID = c.PersonID
INNER JOIN Person.Person AS p ON p.BusinessEntityID = bec.BusinessEntityID
GROUP BY p.FirstName , p.LastName, soh.CustomerID;

Answer 1

您的查询运行，它只返回一个空的结果集。

如果您查看BusinessEntityContact，则会将BusinessEntityID（一个客户业务）与PersonID相关联，SELECT soh.CustomerID AS 'Customer ID', p.FirstName + ' ' + p.LastName AS 'Customer Name', AVG(soh.TotalDue) AS 'Average Sales Amount Per Customer' FROM Sales.SalesOrderHeader AS soh INNER JOIN Sales.Customer AS c ON c.CustomerID = soh.CustomerID INNER JOIN Person.BusinessEntityContact AS bec ON bec.PersonID = c.PersonID INNER JOIN Person.Person AS p ON p.BusinessEntityID = bec.PersonID GROUP BY p.FirstName , p.LastName, soh.CustomerID;是该业务的联系人。因此，如果您将查询更改为：

{{1}}

（注意第三个内连接）你会得到635行。

Answer 2

在SQL单引号＆＃39;识别一个字符串。如果您必须在结果列名称中包含空格，那么您可以使用双引号标识列名称＆＃34;或者最好将列名包装在方括号中。

SELECT  
     soh.CustomerID AS [Customer ID]
    ,p.FirstName + ' ' + p.LastName AS [Customer Name]
    ,AVG(soh.TotalDue) AS [Average Sales Amount Per Customer]
FROM  Sales.SalesOrderHeader AS soh
   INNER JOIN Sales.Customer AS c ON c.CustomerID = soh.CustomerID
   INNER JOIN Person.BusinessEntityContact AS bec ON bec.PersonID = c.PersonID
   INNER JOIN Person.Person AS p ON p.BusinessEntityID = bec.BusinessEntityID
GROUP BY p.FirstName , p.LastName, soh.CustomerID;

否则你的语法对我来说没问题

使用AdventureWorks2012查找每位客户的平均销售额

2 个答案: