如果列名称是 XPath 节点测试中的一个,则内容将进行映射,如下表所示。 当列名称为 XPath 节点测试时,内容将映射到相应的节点。 如果列的 SQL 类型为 xml,则返回错误。
| 列名 | 行为 |
|---|---|
| text() | 对于名称为 text 的列(),该列中的字符串值将添加为文本节点。 |
| comment() | 对于具有 comment 名称的列(),该列中的字符串值将添加为 XML 注释。 |
| node() | 对于名称为node()节点名的列,结果与列名称为通配符字符(*)时的结果相同。 |
| 处理指令(name) | 对于具有处理指令名称的列,该列中的字符串值将添加为处理指令目标名称的 PI 值。 |
以下查询展示了节点测试是如何作为列名称使用的。 它会在生成的 XML 中添加文本节点和注释。
USE AdventureWorks2012;
GO
SELECT E.BusinessEntityID "@EmpID",
'Example of using node tests such as text(), comment(), processing-instruction()' as "comment()",
'Some PI' as "processing-instruction(PI)",
'Employee name and address data' as "text()",
'middle name is optional' as "EmpName/text()",
FirstName as "EmpName/First",
MiddleName as "EmpName/Middle",
LastName as "EmpName/Last",
AddressLine1 as "Address/AddrLine1",
AddressLine2 as "Address/AddrLIne2",
City as "Address/City"
FROM HumanResources.Employee AS E
INNER JOIN Person.Person AS P
ON P.BusinessEntityID = E.BusinessEntityID
INNER JOIN Person.BusinessEntityAddress AS BAE
ON BAE.BusinessEntityID = E.BusinessEntityID
INNER JOIN Person.Address AS A
ON BAE.AddressID = A.AddressID
WHERE E.BusinessEntityID=1
FOR XML PATH;
结果如下:
<row EmpID="1">
<!--Example of using node tests such as text(), comment(), processing-instruction() -->
<?PI Some PI?>
Employee name and address data
<EmpName>middle name is optional
<First>Ken</First>
<Last>S??nchez</Last>
</EmpName>
<Address>
<AddrLine1>4350 Minute Dr.</AddrLine1>
<City>Minneapolis</City>
</Address>
</row>