SQL SERVER中XML查询：FOR XML指定RAW
前言
在SQL SERVER中，XML查询可以指定RAW，AUTO，EXPLICIT，PATH。本文用一些实例介绍SQL SERVER中指定RAW的XML查询。
基础FOR XML查询
看实例：
with TestXml
as
(
select 1 as id,'LeeWhoeeUniversity' as name
union all
select 2,'SQLSERVER中XML查询'
union all
select 3 ,'FOR XML'
)
select id,name from testxml for xml raw,type
运行后结果：
<row id="1" name="LeeWhoeeUniversity" />
<row id="2" name="SQLSERVER中XML查询" />
<row id="3" name="FOR XML" />
红色字体type可选，不会影响结果，只是影响数据类型。
指定 ELEMENTS：
with TestXml
as
(
select 1 as id,N'LeeWhoeeUniversity' as name
union all
select 2,N'SQLSERVER中XML查询'
union all
select 3 ,null
)
select id,name from testxml for xml raw,elements
注意，第三行值改为NULL值进行测试。
结果：
<row>
<id>1</id>
<name>LeeWhoeeUniversity</name>
</row>
<row>
<id>2</id>
<name>SQLSERVER中XML查询</name>
</row>
<row>
<id>3</id>
</row>
元素name在第三行没有出现，因为是NULL值。
但是我们可以用XSINIL生成NULL值的name元素。
如：
with TestXml
as
(
select 1 as id,N'LeeWhoeeUniversity' as name
union all
select 2,N'SQLSERVER中XML查询'
union all
select 3 ,null
)
select id,name from testxml for xml raw,elements XSINIL
运行结果：
<row xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<id>1</id>
<name>LeeWhoeeUniversity</name>
</row>
<row xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<id>2</id>
<name>SQLSERVER中XML查询</name>
</row>
<row xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<id>3</id>
<name xsi:nil="true" />
</row>
使用XMLDATA和XMLSCHEMA
XMLDATA返回描述文档结构的 XML-DATA 架构。
如：
with TestXml
as
(
select 1 as id,N'LeeWhoeeUniversity' as name
union all
select 2,N'SQLSERVER中XML查询'
union all
select 3 ,null
)
select id,name from testxml for xml raw,XMLDATA
结果：
<Schema name="Schema2" xmlns="urn:schemas-microsoft-com:xml-data" xmlns:dt="urn:schemas-microsoft-com:datatypes">
<ElementType name="row" content="empty" model="closed">
<AttributeType name="id" dt:type="i4" />
<AttributeType name="name" dt:type="string" />
<attribute type="id" />
<attribute type="name" />
</ElementType>
</Schema>
<row xmlns="x-schema:#Schema2" id="1" name="LeeWhoeeUniversity" />
<row xmlns="x-schema:#Schema2" id="2" name="SQLSERVER中XML查询" />
<row xmlns="x-schema:#Schema2" id="3" />
XML SCHEMA
通过指定 XMLSCHEMA 选项，您可以针对结果请求 XSD 架构:
with TestXml
as
(
select 1 as id,N'LeeWhoeeUniversity' as name
union all
select 2,N'SQLSERVER中XML查询'
union all
select 3 ,null
)
select id,name from testxml for xml raw,XMLSCHEMA
结果：
<xsd:schema targetNamespace="urn:schemas-microsoft-com:sql:SqlRowSet2" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:sqltypes="http://schemas.microsoft.com/sqlserver/2004/sqltypes" elementFormDefault="qualified">
<xsd:import namespace="http://schemas.microsoft.com/sqlserver/2004/sqltypes" schemaLocation="http://schemas.microsoft.com/sqlserver/2004/sqltypes/sqltypes.xsd" />
<xsd:element name="row">
<xsd:complexType>
<xsd:attribute name="id" type="sqltypes:int" use="required" />
<xsd:attribute name="name">
<xsd:simpleType>
<xsd:restriction base="sqltypes:nvarchar" sqltypes:localeId="2052" sqltypes:sqlCompareOptions="IgnoreCase IgnoreKanaType IgnoreWidth">
<xsd:maxLength value="12" />
</xsd:restriction>
</xsd:simpleType>
</xsd:attribute>
</xsd:complexType>
</xsd:element>
</xsd:schema>
<row xmlns="urn:schemas-microsoft-com:sql:SqlRowSet2" id="1" name="LeeWhoeeUniversity" />
<row xmlns="urn:schemas-microsoft-com:sql:SqlRowSet2" id="2" name="SQLSERVER中XML查询" />
<row xmlns="urn:schemas-microsoft-com:sql:SqlRowSet2" id="3" />
您可以将目标命名空间 URI 指定为 FOR XML 中 XMLSCHEMA 的可选参数。
with TestXml
as
(
select 1 as id,N'LeeWhoeeUniversity' as name
union all
select 2,N'SQLSERVER中XML查询'
union all
select 3 ,null
)
select id,name from testxml for xml raw,XMLSCHEMA ('urn:http://blog.csdn.net/lihui_830501')
结果：
<xsd:schema targetNamespace="urn:http://blog.csdn.net/lihui_830501" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:sqltypes="http://schemas.microsoft.com/sqlserver/2004/sqltypes" elementFormDefault="qualified">
<xsd:import namespace="http://schemas.microsoft.com/sqlserver/2004/sqltypes" schemaLocation="http://schemas.microsoft.com/sqlserver/2004/sqltypes/sqltypes.xsd" />
<xsd:element name="row">
<xsd:complexType>
<xsd:attribute name="id" type="sqltypes:int" use="required" />
<xsd:attribute name="name">
<xsd:simpleType>
<xsd:restriction base="sqltypes:nvarchar" sqltypes:localeId="2052" sqltypes:sqlCompareOptions="IgnoreCase IgnoreKanaType IgnoreWidth">
<xsd:maxLength value="12" />
</xsd:restriction>
</xsd:simpleType>
</xsd:attribute>
</xsd:complexType>
</xsd:element>
</xsd:schema>
<row xmlns="urn:http://blog.csdn.net/lihui_830501" id="1" name="LeeWhoeeUniversity" />
<row xmlns="urn:http://blog.csdn.net/lihui_830501" id="2" name="SQLSERVER中XML查询" />
<row xmlns="urn:http://blog.csdn.net/lihui_830501" id="3" />
检索二进制数据
像XMLDATA一样，在SQL中指定BINARY BASE64。
重命名 <row> 元素
with TestXml
as
(
select 1 as id,N'LeeWhoeeUniversity' as name
union all
select 2,N'SQLSERVER中XML查询'
union all
select 3 ,null
)
select id,name from testxml for xml raw ('myrow')
结果：
<myrow id="1" name="LeeWhoeeUniversity" />
<myrow id="2" name="SQLSERVER中XML查询" />
<myrow id="3" />
指定ELEMENTS的情况类同。
为 FOR XML 生成的 XML 指定根元素
with TestXml
as
(
select 1 as id,N'LeeWhoeeUniversity' as name
union all
select 2,N'SQLSERVER中XML查询'
union all
select 3 ,null
)
select id,name from testxml for xml raw,root('myroot')
结果：
<myroot>
<row id="1" name="LeeWhoeeUniversity" />
<row id="2" name="SQLSERVER中XML查询" />
<row id="3" />
</myroot>
查询 XML 类型的列
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declare @xml table(xid int,xname varchar(50),xmlcol xml);
insert into @xml select 1,'第一行','<myroot>
<row id="1" name="LeeWhoeeUniversity" />
<row id="2" name="SQLSERVER中XML查询" />
<row id="3" />
</myroot>'
insert into @xml select 2,'第二行','<myroot>
<row id="4" name="XML数据" />
<row id="5" name="FOR XML指定RAW" />
</myroot>'
select xid,xname,xmlcol.query('/myroot') from @xml for xml raw
结果：
<row xid="1" xname="第一行">
<myroot>
<row id="1" name="LeeWhoeeUniversity" />
<row id="2" name="SQLSERVER中XML查询" />
<row id="3" />
</myroot>
</row>
<row xid="2" xname="第二行">
<myroot>
<row id="4" name="XML数据" />
<row id="5" name="FOR XML指定RAW" />
</myroot>
</row>
总结
以上对指定RAW的XML查询就介绍完了，下一篇文章将继续用实例介绍SQL SERVER中的XML查询：指定AUTO查询。
