SQL Server：使用 FOR XML PATH 嵌套元素

Question

努力编写可以在 XML 中生成嵌套元素的查询。谁能帮忙

输入：

SELECT EmpName AS [Name],
       EmpDOB       AS [Birthdate],
       EmpSalary        AS [WageAmount],
    Add1    AS [Address1],
    Add2    AS [Address2],
    Mobile  AS [Mobile]
FROM   Employee
FOR XML PATH 

输出：（这有附加信息作为嵌套元素）

<Employee>
<Name>Conrad</Name>
<Birthdate>14-oct-76</BirthDate>
<WageAmount>10000</WageAmount>
<AdditionalInfo>
    <Address1>Washington DC</Address1>
    <Address2>DC</Address2>
    <Mobile>989898989</Mobile>
</AdditionalInfo>
</Employee>

Answer 1

在这种情况下，简单的方法是使用正斜杠分隔符指定列别名中的路径：

SELECT EmpName AS [Name],
       EmpDOB AS [Birthdate],
       EmpSalary AS [WageAmount],
       Add1 AS [AdditionalInfo/Address1],
       Add2 AS [AdditionalInfo/Address2],
       Mobile AS [AdditionalInfo/Mobile]
FROM   Employee
FOR XML PATH ('Employee')

您还可以使用在选择列中返回 XML 的子查询来实现。像这样的东西：

SELECT EmpName AS [Name],
       EmpDOB AS [Birthdate],
       EmpSalary AS [WageAmount],
       (select
           Add1 AS [AdditionalInfo/Address1],
           Add2 AS [AdditionalInfo/Address2],
           Mobile AS [AdditionalInfo/Mobile]
        from Employee EmpAddInfo
        where EmpAddInfo.EmployeeID=Employee.EmployeeID
        FOR XML PATH('AdditionalInfo'), TYPE 
        )
FROM Employee
FOR XML PATH ('Employee')

在您的情况下这样做很愚蠢，因为这些字段都在同一个表中，但是如果您有一个要加入的详细信息表，您会这样做。