SQL Server解析XML数据的方法详解

(编辑：jimmy 日期: 2024/11/24 浏览：3 次 )

本文实例讲述了SQL Server解析XML数据的方法。分享给大家供大家参考，具体如下：

--5.读取XML
--下面为多种方法从XML中读取EMAIL
DECLARE @x XML
SELECT @x = '
<People>
  <dongsheng>
    <Info Name="Email">dongsheng@xxyy.com</Info>
    <Info Name="Phone">678945546</Info>
    <Info Name="qq">36575</Info>
  </dongsheng>
</People>'
-- 方法1
SELECT @x.value('data(/People/dongsheng/Info[@Name="Email"])[1]', 'varchar(30)')
-- 方法2
SELECT @x.value('(/People/dongsheng/Info[@Name="Email"])[1]', 'varchar(30)')
-- 方法3
SELECT
  C.value('.','varchar(30)')
FROM @x.nodes('/People/dongsheng/Info[@Name="Email"]') T(C)
-- 方法4
SELECT
  C.value('(Info[@Name="Email"])[1]','varchar(30)')
FROM @x.nodes('/People/dongsheng') T(C)
-- 方法5
SELECT
  C.value('(dongsheng/Info[@Name="Email"])[1]','varchar(30)')
FROM @x.nodes('/People') T(C)
-- 方法6
SELECT
  C.value('.','varchar(30)')
FROM @x.nodes('/People/dongsheng/Info') T(C)
WHERE C.value('(.[@Name="Email"])[1]','varchar(30)') IS NOT NULL
-- 方法7
SELECT
  C.value('.','varchar(30)')
FROM @x.nodes('/People/dongsheng/Info') T(C)
WHERE C.exist('(.[@Name="Email"])[1]') = 1
--6.Reading values from an XML variable
DECLARE @x XML
SELECT @x =
'<Peoples>
  <People Name="tudou" Sex="女" />
  <People Name="choushuigou" Sex="女"/>
  <People Name="dongsheng" Sex="男" />
</Peoples>'
SELECT
  v.value('@Name[1]','VARCHAR(20)') AS Name,
  v.value('@Sex[1]','VARCHAR(20)') AS Sex
FROM @x.nodes('/Peoples/People') x(v)
--7.多属性过滤
DECLARE @x XML
SELECT @x = '
<Employees>
 <Employee id="1234" dept="IT" type="合同工">
  <Info NAME="dongsheng" SEX="男" QQ="5454545454"/>
 </Employee>
 <Employee id="5656" dept="IT" type="临时工">
  <Info NAME="土豆" SEX="女" QQ="5345454554"/>
 </Employee>
 <Employee id="3242" dept="市场" type="合同工">
  <Info NAME="choushuigou" SEX="女" QQ="54543545"/>
 </Employee>
</Employees>'
--查询dept为IT的人员信息
  --方法1
  SELECT
    C.value('@NAME[1]','VARCHAR(10)') AS NAME,
    C.value('@SEX[1]','VARCHAR(10)') AS SEX,
    C.value('@QQ[1]','VARCHAR(20)') AS QQ
  FROM @x.nodes('/Employees/Employee[@dept="IT"]/Info') T(C)
  /*
  NAME   SEX    QQ
  ---------- ---------- --------------------
  dongsheng 男     5454545454
  土豆   女     5345454554
  */
  --方法2
  SELECT
    C.value('@NAME[1]','VARCHAR(10)') AS NAME,
    C.value('@SEX[1]','VARCHAR(10)') AS SEX,
    C.value('@QQ[1]','VARCHAR(20)') AS QQ
  FROM @x.nodes('//Employee[@dept="IT"]/*') T(C)
  /*
  NAME   SEX    QQ
  ---------- ---------- --------------------
  dongsheng 男     5454545454
  土豆   女     5345454554
  */
--查询出IT部门type为Permanent的员工
SELECT
  C.value('@NAME[1]','VARCHAR(10)') AS NAME,
  C.value('@SEX[1]','VARCHAR(10)') AS SEX,
  C.value('@QQ[1]','VARCHAR(20)') AS QQ
FROM @x.nodes('//Employee[@dept="IT"][@type="合同工"]/*') T(C)
/*
  NAME   SEX    QQ
  ---------- ---------- --------------------
  dongsheng 男     5454545454
*/
--12.从XML变量中删除元素
DECLARE @x XML
SELECT @x = '
<Peoples>
 <People>
   <NAME>土豆</NAME>
   <SEX>男</SEX>
   <QQ>5345454554</QQ>
 </People>
</Peoples>'
SET @x.modify('
  delete (/Peoples/People/SEX)[1]'
 )
SELECT @x
/*
<Peoples>
 <People>
  <NAME>土豆</NAME>
  <QQ>5345454554</QQ>
 </People>
</Peoples>
*/
--19.读取指定变量元素的值
DECLARE @x XML
SELECT @x = '
<Peoples>
 <People>
   <NAME>dongsheng</NAME>
   <SEX>男</SEX>
   <QQ>423545</QQ>
 </People>
 <People>
   <NAME>土豆</NAME>
   <SEX>男</SEX>
   <QQ>123133</QQ>
 </People>
 <People>
   <NAME>choushuigou</NAME>
   <SEX>女</SEX>
   <QQ>54543545</QQ>
 </People>
</Peoples>
'
DECLARE @ElementName VARCHAR(20)
SELECT @ElementName = 'NAME'
SELECT c.value('.','VARCHAR(20)') AS NAME
FROM @x.nodes('/Peoples/People/*[local-name()=sql:variable("@ElementName")]') T(C)
/*
NAME
--------------------
dongsheng
土豆
choushuigou
*/
--20使用通配符读取元素值
--读取根元素的值
DECLARE @x1 XML
SELECT @x1 = '<People>dongsheng</People>'
SELECT @x1.value('(/*/text())[1]','VARCHAR(20)') AS People --星号*代表一个元素
/*
People
--------------------
dongsheng
*/
--读取第二层元素的值
DECLARE  @x XML
SELECT @x = '
 <People>
   <NAME>dongsheng</NAME>
   <SEX>男</SEX>
   <QQ>423545</QQ>
 </People>'
SELECT
  @x.value('(/*/*/text())[1]','VARCHAR(20)') AS NAME
/*
NAME
--------------------
dongsheng
*/
--读取第二个子元素的值
DECLARE  @x XML
SELECT @x = '
 <People>
   <NAME>dongsheng</NAME>
   <SEX>男</SEX>
   <QQ>423545</QQ>
 </People>'
SELECT
  @x.value('(/*/*/text())[2]','VARCHAR(20)') AS SEX
/*
SEX
--------------------
男
*/
--读取所有第二层子元素值
DECLARE  @x XML
SELECT @x = '
 <People>
   <NAME>dongsheng</NAME>
   <SEX>男</SEX>
   <QQ>423545</QQ>
 </People>'
SELECT
  C.value('.','VARCHAR(20)') AS value
FROM @x.nodes('/*/*') T(C)
/*
value
--------------------
dongsheng
男
423545
*/
--21.使用通配符读取元素名称
DECLARE @x XML
SELECT @x = '<People>dongsheng</People>'
SELECT
  @x.value('local-name(/*[1])','VARCHAR(20)') AS ElementName
/*
ElementName
--------------------
People
*/
--读取根下第一个元素的名称和值
DECLARE  @x XML
SELECT @x = '
 <People>
   <NAME>dongsheng</NAME>
   <SEX>男</SEX>
 </People>'
SELECT
  @x.value('local-name((/*/*)[1])','VARCHAR(20)') AS ElementName,
  @x.value('(/*/*/text())[1]','VARCHAR(20)') AS ElementValue
/*
ElementName     ElementValue
-------------------- --------------------
NAME         dongsheng
*/
--读取根下第二个元素的名称和值
DECLARE  @x XML
SELECT @x = '
 <People>
   <NAME>dongsheng</NAME>
   <SEX>男</SEX>
 </People>'
SELECT
  @x.value('local-name((/*/*)[2])','VARCHAR(20)') AS ElementName,
  @x.value('(/*/*/text())[2]','VARCHAR(20)') AS ElementValue
/*
ElementName     ElementValue
-------------------- --------------------
SEX         男
*/
--读取根下所有的元素名称和值
DECLARE  @x XML
SELECT @x = '
 <People>
   <NAME>dongsheng</NAME>
   <SEX>男</SEX>
 </People>'
SELECT
  C.value('local-name(.)','VARCHAR(20)') AS ElementName,
  C.value('.','VARCHAR(20)') AS ElementValue
FROM @x.nodes('/*/*') T(C)
/*
ElementName     ElementValue
-------------------- --------------------
NAME         dongsheng
SEX         男
*/
---22.查询元素数量
--如下Peoples根节点下有个People子节点。
DECLARE @x XML
SELECT @x = '
<Peoples>
 <People>
   <NAME>dongsheng</NAME>
   <SEX>男</SEX>
 </People>
 <People>
   <NAME>土豆</NAME>
   <SEX>男</SEX>
 </People>
 <People>
   <NAME>choushuigou</NAME>
   <SEX>女</SEX>
 </People>
</Peoples>
'
SELECT  @x.value('count(/Peoples/People)','INT') AS Children
/*
Children
-----------
3
*/
--如下Peoples根节点下第一个子节点People下子节点的数量
SELECT  @x.value('count(/Peoples/People[1]/*)','INT') AS Children
/*
Children
-----------
2
*/
--某些时候我们可能不知道根节点和子节点的名称，可以用通配符来代替。
SELECT  @x.value('count(/*/*)','INT') AS ChildrenOfRoot,
     @x.value('count(/*/*[1]/*)','INT') AS ChildrenOfFirstChildElement
/*
ChildrenOfRoot ChildrenOfFirstChildElement
-------------- ---------------------------
3       2
*/
--23.查询属性的数量
DECLARE @x XML
SELECT @x = '
<Employees dept="IT">
  <Employee NAME="dongsheng" SEX="男" QQ="5454545454"/>
  <Employee NAME="土豆" SEX="女" QQ="5345454554" TEL="13954697895"/>
</Employees>'
--查询跟节点的属性数量
SELECT  @x.value('count(/Employees/@*)','INT') AS AttributeCountOfRoot
/*
AttributeCountOfRoot
--------------------
1
*/
--第一个Employee节点的属性数量
SELECT  @x.value('count(/Employees/Employee[1]/@*)','INT') AS AttributeCountOfFirstElement
/*
AttributeCountOfFirstElement
----------------------------
3
*/
--第二个Employee节点的属性数量
SELECT  @x.value('count(/Employees/Employee[2]/@*)','INT') AS AttributeCountOfSeconfElement
/*
AttributeCountOfSeconfElement
-----------------------------
4
*/
--如果不清楚节点名称可以用*通配符代替
SELECT  @x.value('count(/*/@*)','INT') AS AttributeCountOfRoot
    ,@x.value('count(/*/*[1]/@*)','INT') AS AttributeCountOfFirstElement
    ,@x.value('count(/*/*[2]/@*)','INT') AS AttributeCountOfSeconfElement
/*
AttributeCountOfRoot AttributeCountOfFirstElement AttributeCountOfSeconfElement
-------------------- ---------------------------- -----------------------------
1          3              4
*/
--返回没个节点的属性值
SELECT  C.value('count(./@*)','INT') AS AttributeCount
FROM @x.nodes('/*/*') T(C)
/*
AttributeCount
--------------
3
4
*/
--24.返回给定位置的属性值或者名称
DECLARE @x XML
SELECT @x = '
<Employees dept="IT">
  <Employee NAME="dongsheng" SEX="男" QQ="5454545454"/>
  <Employee NAME="土豆" SEX="女" QQ="5345454554" TEL="13954697895"/>
</Employees>'
--返回第一个Employee节点的第一个位置的属性值
SELECT  @x.value('(/Employees/Employee[1]/@*[position()=1])[1]','VARCHAR(20)') AS AttValue
/*
AttValue
--------------------
dongsheng
*/
--返回第二个Employee节点的第四个位置的属性值
SELECT  @x.value('(/Employees/Employee[2]/@*[position()=4])[1]','VARCHAR(20)') AS AttValue
/*
AttValue
--------------------
13954697895
*/
--返回第一个元素的第三个属性值
SELECT  @x.value('local-name((/Employees/Employee[1]/@*[position()=3])[1])','VARCHAR(20)') AS AttName
/*
AttName
--------------------
QQ
*/
--返回第二个元素的第四个属性值
SELECT  @x.value('local-name((/Employees/Employee[2]/@*[position()=4])[1])','VARCHAR(20)') AS AttName
/*
AttName
--------------------
TEL
*/
--通过变量传递位置返回属性值
DECLARE @Elepos INT,@Attpos INT
SELECT @Elepos=2,@Attpos = 3
SELECT  @x.value('local-name((/Employees/Employee[sql:variable("@Elepos")]/@*[position()=sql:variable("@Attpos")])[1])','VARCHAR(20)') AS AttName
/*
AttName
--------------------
QQ
*/
--25.判断是XML中否存在相应的属性
DECLARE  @x XML
SELECT @x = '<Employee NAME="土豆" SEX="女" QQ="5345454554" TEL="13954697895"/>'
IF @x.exist('/Employee/@NAME') = 1
  SELECT 'Exists' AS Result
ELSE
  SELECT 'Does not exist' AS Result
/*
Result
------
Exists
*/
--传递变量判断是否存在
DECLARE  @x XML
SELECT @x = '<Employee NAME="土豆" SEX="女" QQ="5345454554" TEL="13954697895"/>'
DECLARE @att VARCHAR(20)
SELECT @att = 'QQ'
IF @x.exist('/Employee/@*[local-name()=sql:variable("@att")]') = 1
  SELECT 'Exists' AS Result
ELSE
  SELECT 'Does not exist' AS Result
/*
Result
------
Exists
*/
--26.循环遍历元素的所有属性
DECLARE  @x XML
SELECT @x = '<Employee NAME="土豆" SEX="女" QQ="5345454554" TEL="13954697895"/>'
DECLARE
  @cnt INT,
  @totCnt INT,
  @attName VARCHAR(30),
  @attValue VARCHAR(30)
SELECT
  @cnt = 1,
  @totCnt = @x.value('count(/Employee/@*)','INT')--获得属性总数量
-- loop
WHILE @cnt <= @totCnt BEGIN
  SELECT
    @attName = @x.value(
      'local-name((/Employee/@*[position()=sql:variable("@cnt")])[1])',
      'VARCHAR(30)'),
    @attValue = @x.value(
      '(/Employee/@*[position()=sql:variable("@cnt")])[1]',
      'VARCHAR(30)')
  PRINT 'Attribute Position: ' + CAST(@cnt AS VARCHAR)
  PRINT 'Attribute Name: ' + @attName
  PRINT 'Attribute Value: ' + @attValue
  PRINT ''
  -- increment the counter variable
  SELECT @cnt = @cnt + 1
END
/*
Attribute Position: 1
Attribute Name: NAME
Attribute Value: 土豆
Attribute Position: 2
Attribute Name: SEX
Attribute Value: 女
Attribute Position: 3
Attribute Name: QQ
Attribute Value: 5345454554
Attribute Position: 4
Attribute Name: TEL
Attribute Value: 13954697895
*/
--27.返回指定位置的子元素
DECLARE @x XML
SELECT @x = '
<Employees dept="IT">
  <Employee NAME="dongsheng" SEX="男" QQ="5454545454"/>
  <Employee NAME="土豆" SEX="女" QQ="5345454554" TEL="13954697895"/>
</Employees>'
SELECT @x.query('(/Employees/Employee)[1]')
/*
<Employee NAME="dongsheng" SEX="男" QQ="5454545454" />
*/
SELECT @x.query('(/Employees/Employee)[position()=2]')
/*
<Employee NAME="土豆" SEX="女" QQ="5345454554" TEL="13954697895" />
*/
--通过变量获取指定位置的子元素
DECLARE @i INT
SELECT @i = 2
SELECT @x.query('(/Employees/Employee)[sql:variable("@i")]')
--or
SELECT @x.query('(/Employees/Employee)[position()=sql:variable("@i")]')
/*
<Employee NAME="土豆" SEX="女" QQ="5345454554" TEL="13954697895" />
*/
--28.循环遍历获得所有子元素
DECLARE @x XML
SELECT @x = '
<Employees dept="IT">
  <Employee NAME="dongsheng" SEX="男" QQ="5454545454"/>
  <Employee NAME="土豆" SEX="女" QQ="5345454554" TEL="13954697895"/>
</Employees>'
DECLARE
  @cnt INT,
  @totCnt INT,
  @child XML
-- counter variables
SELECT
  @cnt = 1,
  @totCnt = @x.value('count(/Employees/Employee)','INT')
-- loop
WHILE @cnt <= @totCnt BEGIN
  SELECT
    @child = @x.query('/Employees/Employee[position()=sql:variable("@cnt")]')
  PRINT 'Processing Child Element: ' + CAST(@cnt AS VARCHAR)
  PRINT 'Child element: ' + CAST(@child AS VARCHAR(100))
  PRINT ''
  -- incremet the counter variable
  SELECT @cnt = @cnt + 1
END
/*
Processing Child Element: 1
Child element: <Employee NAME="dongsheng" SEX="男" QQ="5454545454"/>
Processing Child Element: 2
Child element: <Employee NAME="土豆" SEX="女" QQ="5345454554" TEL="13954697895"/>

SQL Server 中对XML数据的五种基本操作

1.xml.exist
   输入为XQuery表达式，返回0，1或是Null。0表示不存在，1表示存在，Null表示输入为空
2.xml.value
   输入为XQuery表达式，返回一个SQL Server标量值
3.xml.query
   输入为XQuery表达式，返回一个SQL Server XML类型流
4.xml.nodes
   输入为XQuery表达式，返回一个XML格式文档的一列行集
5.xml.modify

使用XQuery表达式对XML的节点进行insert , update 和 delete 操作。

下面通过例子对上面的五种操作进行说明：

declare @XMLVar xml = '
<catalog>
    <book category="ITPro">
       <title>Windows Step By Step</title>
       <author>Bill Zack</author>
       <price>49.99</price>
    </book>
    <book category="Developer">
       <title>Developing ADO .NET</title>
       <author>Andrew Brust</author>
       <price>39.93</price>
    </book>
    <book category="ITPro">
       <title>Windows Cluster Server</title>
       <author>Stephen Forte</author>
       <price>59.99</price>
    </book>
</catalog>'

1. xml.exist

select @XMLVar.exist('/catalog/book')-----返回1
select @XMLVar.exist('/catalog/book/@category')-----返回1
select @XMLVar.exist('/catalog/book1')-----返回0
set @XMLVar = null
select @XMLVar.exist('/catalog/book')-----返回null

2.xml.value

select @XMLVar.value('/catalog[1]/book[1]','varchar(MAX)')
select @XMLVar.value('/catalog[1]/book[2]/@category','varchar(MAX)')
select @XMLVar.value('/catalog[2]/book[1]','varchar(MAX)')

结果集为：
Windows Step By StepBill Zack49.99 Developer NULL
3.xml.query

select @XMLVar.query('/catalog[1]/book')
select @XMLVar.query('/catalog[1]/book[1]')
select @XMLVar.query('/catalog[1]/book[2]/author')

结果集分别为：

<book category="ITPro">
 <title>Windows Step By Step</title>
 <author>Bill Zack</author>
 <price>49.99</price>
</book>
<book category="Developer">
 <title>Developing ADO .NET</title>
 <author>Andrew Brust</author>
 <price>39.93</price>
</book>
<book category="ITPro">
 <title>Windows Cluster Server</title>
 <author>Stephen Forte</author>
 <price>59.99</price>
</book>
<book category="ITPro">
 <title>Windows Step By Step</title>
 <author>Bill Zack</author>
 <price>49.99</price>
</book>
<author>Andrew Brust</author>

4.xml.nodes

select T.c.query('.') as result from @XMLVar.nodes('/catalog/book') as T(c)
select T.c.query('title') as result from @XMLVar.nodes('/catalog/book') as T(c)

结果集分别为：

<book category="ITPro"><title>Windows Step By Step</title><author>Bill …………
<book category="Developer"><title>Developing ADO .NET</title><author>Andrew …………
<book category="ITPro"><title>Windows Cluster Server</title><author>Stephen …………
<title>Windows Step By Step</title>
<title>Developing ADO .NET</title>
<title>Windows Cluster Server</title>

set ARITHABORT on
DECLARE @x XML
SELECT @x = '<Peoples>
<People>
    <Email>1dongsheng@xxyy.com</Email>
    <Phone>678945546</Phone>
    <QQ>36575</QQ>
    <Addr>36575</Addr>
</People>
</Peoples>'
-- 方法1
select 1001 as peopleId, p.* FROM(
SELECT
  C.value('local-name(.)','VARCHAR(20)') AS attrName,
  C.value('.','VARCHAR(20)') AS attrValue
FROM @x.nodes('/*/*/*') T(C) --第三层
) as p
/*
1001  Email  1dongsheng@xxyy.com
1001  Phone  678945546
1001  QQ 36575
1001  Addr  36575
*/

/*
 解析XML存储过程
*/
ALTER PROCEDURE [dbo].[sp_ExportXml]
 @x xml ,
 @layerstr nvarchar(max)
AS
  DECLARE @sql nvarchar(max)
BEGIN
   set arithabort on
    set @sql='select p.* FROM(
    SELECT
        C.value(''local-name(.)'',''VARCHAR(20)'') AS attrName,
        C.value(''.'',''VARCHAR(20)'') AS attrValue
    FROM @xmlParas.nodes('''+@layerstr+''') T(C)
    ) as p'
  --print @sql
   EXECUTE sp_executesql @sql, N'@xmlParas as xml',@xmlParas=@x
END

DECLARE @x XML
SELECT @x =
'<Peoples>
<People>
    <Email>1dongsheng@xxyy.com</Email>
    <Phone>678945546</Phone>
    <QQ>36575</QQ>
    <Addr>36575</Addr>
</People>
</Peoples>'
EXECUTE sp_ExportXml @x,'/*/*/*'

希望本文所述对大家SQL Server数据库程序设计有所帮助。

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