查询XML列

Question

我有一个XML列，其格式为：

<methodResponse>
  <params>
    <param>
      <value>
        <struct>
          <member>
            <name>SubscriberBalanceBefore</name>
            <value>
              <string>0.0</string>
            </value>
          </member>
          <member>
            <name>TimeStamp</name>
            <value>
              <dateTime.iso8601>20200812T12:31:10</dateTime.iso8601>
            </value>
          </member>
          <member>
            <name>Subsc riberMSISDN</name>
            <value>
              <string>83000000</string>
            </value>
          </member>
          <member>
            <name>TransactionID</name>
            <value>
              <string>8035768</string>
            </value>
          </member>
        </struct>
      </value>
    </param>
  </params>
</methodResponse>

我希望得到如下表所示的结果：

-------------------------
name      | TransactionID
----------|---------------
830000000 | 8035768

我尝试使用CROSS和OUTER APPLY，但是它不起作用：

SELECT 
    X.Y.value('(name)[3]', 'VARCHAR(max)') as NAME_FIELD,
    X.Y.value('(value/string)[4]', 'varchar(max)') DATA_CONTENT
FROM [TABLE] T
OUTER APPLY T.xmlIn.nodes('methodResponse/params/param/value/struct/member') as X(Y)

它不给出错误，但两个字段都返回null。有人可以帮忙吗？

Answer 1

您的单例标识符不正确。例如，(name)[3]将引用name节点的每个中的第三个member节点。每个成员只有1个name节点，因此NULL值。

您需要分别引用第3个和第member个节点：

DECLARE @XML xml = '<methodResponse>
  <params>
    <param>
      <value>
        <struct>
          <member>
            <name>SubscriberBalanceBefore</name>
            <value>
              <string>0.0</string>
            </value>
          </member>
          <member>
            <name>TimeStamp</name>
            <value>
              <dateTime.iso8601>20200812T12:31:10</dateTime.iso8601>
            </value>
          </member>
          <member>
            <name>Subsc riberMSISDN</name>
            <value>
              <string>83000000</string>
            </value>
          </member>
          <member>
            <name>TransactionID</name>
            <value>
              <string>8035768</string>
            </value>
          </member>
        </struct>
      </value>
    </param>
  </params>
</methodResponse>'

SELECT X.Y.value('(member[3]/value/string/text())[1]', 'varchar(max)') as NAME_FIELD, --Does this need to be a varchar(MAX)? Why not an int?
       X.Y.value('(member[4]/value/string/text())[1]', 'varchar(max)') DATA_CONTENT --Does this need to be a varchar(MAX)? Why not an int?
FROM (VALUES(@XML))T(xmlIn)
OUTER APPLY T.xmlIn.nodes('methodResponse/params/param/value/struct') as X(Y);

但是请注意，上述解决方案取决于节点的顺序位置。使用XPATH和一些布尔逻辑，您可以避免这种情况：

SELECT X.Y.value('(member[name/text()="Subsc riberMSISDN"]/value/string/text())[1]', 'int') as NAME_FIELD,
       X.Y.value('(member[name/text()="TransactionID"]/value/string/text())[1]', 'int') DATA_CONTENT
FROM (VALUES(@XML))T(xmlIn)
OUTER APPLY T.xmlIn.nodes('methodResponse/params/param/value/struct') as X(Y);