在类型化xml列上选择节点的原子值

Question

-- Add schema
CREATE XML SCHEMA COLLECTION MySchema AS N'<xs:schema xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xmlns:xs="http://www.w3.org/2001/XMLSchema"
            attributeFormDefault="unqualified"
            elementFormDefault="qualified"
            xmlns="http://mynamespace"
            targetNamespace="http://mynamespace">

  <xs:element name="element1" type="element1Type">
  </xs:element>

  <xs:complexType name="element1Type">
    <xs:sequence minOccurs="0" maxOccurs="unbounded">
      <xs:element name="element2" type="element2Type" />
    </xs:sequence>
  </xs:complexType>

  <xs:complexType name="element2Type">
    <xs:sequence>
      <xs:element name="element3" type="element3Type" minOccurs="0" maxOccurs="unbounded" />
    </xs:sequence>
  </xs:complexType>

  <xs:complexType name="element3Type">
    <xs:sequence minOccurs="0">
      <xs:element minOccurs="0" name="element4" />
    </xs:sequence>
  </xs:complexType>

</xs:schema>'
GO

-- Create table
CREATE TABLE [dbo].[MyTable](
    [XmlColumn] [xml](CONTENT [dbo].[MySchema]) NOT NULL
)
GO

-- Add test data
INSERT INTO MyTable SELECT N'<element1 xmlns="http://mynamespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <element2>
    <element3>
      <element4>my text here</element4>
    </element3>
  </element2>
</element1>'
GO

-- run query
WITH XMLNAMESPACES(
    'http://mynamespace' as s,
    DEFAULT 'http://mynamespace'
)
SELECT 
    T.rows.value('(element3/element4)[1]/text()', 'varchar(100)') as [AtomicValue]
FROM
    MyTable
CROSS APPLY
    XmlColumn.nodes('/element1/element2') T(rows)

XQuery [MyTable.XmlColumn.value()]: 'text()' is not supported on simple typed or
'http://www.w3.org/2001/XMLSchema#anyType' elements, found
'element({http://mynamespace}:element4,xs:anyType) ?'.

Answer 1

您可以使用query，然后使用value。

WITH XMLNAMESPACES(
    'http://mynamespace' as s,
    DEFAULT 'http://mynamespace'
)
SELECT 
    T.rows.query('element3/element4').value('.', 'varchar(100)')
FROM
    MyTable
CROSS APPLY
    XmlColumn.nodes('/element1/element2') T(rows)

也可以在架构中指定element4的类型。

<xs:element minOccurs="0" name="element4" type="xs:string"/>

并使用此查询

WITH XMLNAMESPACES(
    'http://mynamespace' as s,
    DEFAULT 'http://mynamespace'
)
SELECT 
    T.rows.value('(element3/element4)[1]', 'varchar(100)') as [AtomicValue]
FROM
    MyTable
CROSS APPLY
    XmlColumn.nodes('/element1/element2') T(rows)