如何使用XQuery

时间:2018-08-16 12:55:11

标签: tsql xpath xquery sql-server-2014-express flwor

鉴于下面的XML结构,我需要过滤掉question值等于<questionSubType/>ABC属性等于{的所有<option subType=""/>节点{1}}:

001

我尝试了以下操作,但是由于我不确定如何继续查询<questions> <question> <text>Some text</text> <questionType></questionType> <questionSubType>ABC</questionSubType> <options> <option subType="001"> <text>Y</text> <mappedCodes> <code>1</code> </mappedCodes> </option> <option subType="001"> <text>N</text> <mappedCodes> <code>2</code> </mappedCodes> </option> <option subType="002"> <text>Y</text> <mappedCodes> <code>1</code> </mappedCodes> </option> </options> </question> <question> <text>Some more text</text> <questionType></questionType> <questionSubType>DEF</questionSubType> <options> <option subType="001"> <text>Single</text> <mappedCodes> <code>PL0157</code> </mappedCodes> </option> <option subType="001"> <text>Married</text> <mappedCodes> <code>PD0241</code> </mappedCodes> </option> <option subType="002"> <text>Single</text> <mappedCodes> <code>PL1157</code> </mappedCodes> </option> <option subType="002"> <text>Married</text> <mappedCodes> <code>PD1241</code> </mappedCodes> </option> </options> </question> <question> <text>Some last text</text> <questionType></questionType> <questionSubType>ABC</questionSubType> <options> <option subType="001"> <text>T</text> <mappedCodes> <code>2</code> </mappedCodes> </option> <option subType="002"> <text>V</text> <mappedCodes> <code>2</code> </mappedCodes> </option> </options> </question> </questions> 节点,因此这仅基于<questionSubType/>值过滤XML:

<option/>

因此,最后,我的输出应如下所示:

        DECLARE
            @subType varchar(5) = '001'
          , @questionSubType varchar(5) = 'ABC'
        SET @XmlOutput = (
            SELECT
                1 as Tag 
              , null as Parent
              , CONVERT(nvarchar(max), F.N.query('./*')) as [question!1!!XML]
            FROM [MyTable] T
                CROSS APPLY T.[Configuration].nodes('//question') F(N)
            WHERE
                F.N.value('(//questionSubType/text())[1]', 'varchar(100)') = @questionSubType
            FOR XML EXPLICIT, ROOT('questions')
        )

        SELECT @XmlOutput as [Configuration]

任何帮助将不胜感激。

1 个答案:

答案 0 :(得分:1)

这里XQuery是您的救命之路:

DECLARE @xml XML=
N'<questions>
  <question>
    <text>Some text</text>
    <questionType></questionType>
    <questionSubType>ABC</questionSubType>
    <options>
      <option subType="001">
        <text>Y</text>
        <mappedCodes>
          <code>1</code>
        </mappedCodes>
      </option>
      <option subType="001">
        <text>N</text>
        <mappedCodes>
          <code>2</code>
        </mappedCodes>
      </option>
      <option subType="002">
        <text>Y</text>
        <mappedCodes>
          <code>1</code>
        </mappedCodes>
      </option>
    </options>
  </question>
  <question>
    <text>Some more text</text>
    <questionType></questionType>
    <questionSubType>DEF</questionSubType>    
    <options>
      <option subType="001">
        <text>Single</text>
        <mappedCodes>
          <code>PL0157</code>
        </mappedCodes>
      </option>
      <option subType="001">
        <text>Married</text>
        <mappedCodes>
          <code>PD0241</code>
        </mappedCodes>
      </option>
      <option subType="002">
        <text>Single</text>
        <mappedCodes>
          <code>PL1157</code>
        </mappedCodes>
      </option>
      <option subType="002">
        <text>Married</text>
        <mappedCodes>
          <code>PD1241</code>
        </mappedCodes>
      </option>
    </options>
  </question>
  <question>
    <text>Some last text</text>
    <questionType></questionType>
    <questionSubType>ABC</questionSubType>
    <options>
      <option subType="001">
        <text>T</text>
        <mappedCodes>
          <code>2</code>
        </mappedCodes>
      </option>
      <option subType="002">
        <text>V</text>
        <mappedCodes>
          <code>2</code>
        </mappedCodes>
      </option>
    </options>
  </question>
 </questions>';

-声明变量

    DECLARE @subType varchar(5) = '001'
           ,@questionSubType varchar(5) = 'ABC';

-XQuery将遍历您的XML,并添加具有给定类型的所有问题,然后添加除<options>之外的所有内部节点。最后一个节点再加上一个过滤谓词:

 SELECT @xml.query
 ('<questions>
   {
    for $q in /questions/question[(questionSubType/text())[1]=sql:variable("@questionSubType")]
    return 
        <question>
        {
        $q/*[local-name()!="options"]
        }
        {
        $q/options/option[@subType=sql:variable("@subType")]
        }
        </question>
   } 
   </questions> 
 ');