到目前为止，我们介绍了单张表的例子，下面将引入一些新的元素：连接。分析以下查询：
SELECT e . [Title],
2: a. [City] ,
AS EmployeeName
FROM [HumanResources]. [Employee] e
ON e. [EmployeeID]
6: = ed . [EmployeeID]
ON [ed]. [AddressID] =
8: [a] . [AddressID]
ON e. [ContactID] =
10: c . [ContactID]