从 SQL 列读取 XML 节点值

Question

我正在尝试从 sql 列中的 xml 提取数据并将其返回到查询结果中，但我一直在努力阅读这个部分 xml。我不确定我做错了什么，或者 xml 的结构方式是否需要不同的方法。我尝试了没有属性和引用的更简单的 XML，并且能够从单个节点中提取。

这些是 XML 文件内容：

<InstanceXmlData xmlns="http://dev.docuware.com/bpw" xmlns:i="http://www.w3.org/2001/XMLSchema-instance">
  <ContextProperties>
    <FieldValue>
      <FieldID>GV_Divisional__Manager</FieldID>
      <Value i:type="AssignToItem">
        <EntryType>User</EntryType>
        <ID>0a28a5ad-db79-4369-9e53-84d0c0bbd0f7</ID>
        <Name>Onward TUBELA</Name>
        <ParentId>00000000-0000-0000-0000-000000000000</ParentId>
      </Value>
    </FieldValue>
    <FieldValue>
      <FieldID>GV_GM__Finance</FieldID>
      <Value i:nil="true" />
    </FieldValue>
    <FieldValue>
      <FieldID>GV_skip__accounts__review</FieldID>
      <Value i:nil="true" />
    </FieldValue>
    <FieldValue>
      <FieldID>DW_DWWorkflowCoreData</FieldID>
      <Value i:type="DWWorkflowCoreData">
        <ActivityName>Accountant Review</ActivityName>
        <AssignToData>
          <Definition>
            <AssignToItem>
              <EntryType>GlobalVariable</EntryType>
              <ID>00000000-0000-0000-0000-000000000000</ID>
              <Name>GV_Accountant</Name>
              <ParentId>00000000-0000-0000-0000-000000000000</ParentId>
            </AssignToItem>
          </Definition>
          <TaskUsers>
            <TaskUser>
              <ID>d1fceeb3-7833-44c2-b6e7-b4883300b987</ID>
              <Name>Hector THOLE</Name>
              <SubstitutionRuleID>00000000-0000-0000-0000-000000000000</SubstitutionRuleID>
            </TaskUser>
          </TaskUsers>
        </AssignToData>
        <CurrentUserId>058b7c3b-9dff-46c2-8654-93b84eb1eac0</CurrentUserId>
        <CurrentUserName>Livhuwani NEMBILWI</CurrentUserName>
        <DocumentLink i:nil="true" />
        <DocumentUserVersion>1.0</DocumentUserVersion>
        <DocumentVersionId>17973</DocumentVersionId>
        <ExpirationDate>0001-01-01T00:00:00</ExpirationDate>
        <FileCabinetID>62005e95-7a62-470e-9fca-c0a2968a22d8</FileCabinetID>
        <HistoryStepCount>25</HistoryStepCount>
        <InstanceStartDate>2020-03-20T14:43:43.9549487Z</InstanceStartDate>
        <NotificationDate>0001-01-01T00:00:00</NotificationDate>
        <OrganizationID>e6674399-4abc-48dc-95a7-7a484ceab4e5</OrganizationID>
        <ReceivedOn>2020-03-31T12:48:15.8432349Z</ReceivedOn>
        <RetryCount>0</RetryCount>
        <TaskLink i:nil="true" />
        <TaskListLink i:nil="true" />
        <TaskUserName>admin</TaskUserName>
        <WorkflowId>bdaee87a-8b5c-4c8e-8cda-c84ec31ae333</WorkflowId>
        <WorkflowName>Journals</WorkflowName>
        <WorkflowVersion>61</WorkflowVersion>
      </Value>
    </FieldValue>
    <FieldValue>
      <FieldID>GV_GM</FieldID>
      <Value i:nil="true" />
    </FieldValue>
    <FieldValue>
      <FieldID>GV_pp__ref</FieldID>
      <Value i:nil="true" />
    </FieldValue>
    <FieldValue>
      <FieldID>GV_query__comment</FieldID>
      <Value xmlns:a="http://www.w3.org/2001/XMLSchema" i:type="a:string">support for the amount not attached </Value>
    </FieldValue>
    <FieldValue>
      <FieldID>GV_Financial__Accounting__Manager</FieldID>
      <Value i:type="AssignToItem">
        <EntryType>User</EntryType>
        <ID>3df4acb0-b321-4845-a274-84e4210914f2</ID>
        <Name>Mmasikati Nkgadima</Name>
        <ParentId>00000000-0000-0000-0000-000000000000</ParentId>
      </Value>
    </FieldValue>
    <FieldValue>
      <FieldID>GV_company__code</FieldID>
      <Value xmlns:a="http://www.w3.org/2001/XMLSchema" i:type="a:string">083H</Value>
    </FieldValue>
    <FieldValue>
      <FieldID>GV_igg</FieldID>
      <Value xmlns:a="http://www.w3.org/2001/XMLSchema" i:type="a:string">MABELKOB</Value>
    </FieldValue>
    <FieldValue>
      <FieldID>GV_Originator</FieldID>
      <Value i:type="AssignToItem">
        <EntryType>User</EntryType>
        <ID>0bfef02c-4222-41b4-bd9f-4e04984b74c7</ID>
        <Name>Mabel KOBE</Name>
        <ParentId>00000000-0000-0000-0000-000000000000</ParentId>
      </Value>
    </FieldValue>
    <FieldValue>
      <FieldID>GV_sap__post__url</FieldID>
      <Value xmlns:a="http://www.w3.org/2001/XMLSchema" i:type="a:string">http://zarmtsaros-ap08:8082/post_to_sap_auto</Value>
    </FieldValue>
    <FieldValue>
      <FieldID>GV_exchange__rate</FieldID>
      <Value xmlns:a="http://www.w3.org/2001/XMLSchema" i:type="a:string">1.8331</Value>
    </FieldValue>
    <FieldValue>
      <FieldID>GV_Line__Manager</FieldID>
      <Value i:type="AssignToItem">
        <EntryType>User</EntryType>
        <ID>cb845699-5dd8-4ea6-98a8-931d0e36f06a</ID>
        <Name>Letsogile Remmonye MOAMPE</Name>
        <ParentId>00000000-0000-0000-0000-000000000000</ParentId>
      </Value>
    </FieldValue>
    <FieldValue>
      <FieldID>GV_posting__month</FieldID>
      <Value xmlns:a="http://www.w3.org/2001/XMLSchema" i:type="a:string">31-03-2020</Value>
    </FieldValue>
    <FieldValue>
      <FieldID>GV_General__Manager</FieldID>
      <Value i:type="AssignToItem">
        <EntryType>User</EntryType>
        <ID>0a28a5ad-db79-4369-9e53-84d0c0bbd0f7</ID>
        <Name>Onward TUBELA</Name>
        <ParentId>00000000-0000-0000-0000-000000000000</ParentId>
      </Value>
    </FieldValue>
    <FieldValue>
      <FieldID>GV_Department</FieldID>
      <Value i:nil="true" />
    </FieldValue>
    <FieldValue>
      <FieldID>GV_Accountant</FieldID>
      <Value i:type="AssignToItem">
        <EntryType>User</EntryType>
        <ID>058b7c3b-9dff-46c2-8654-93b84eb1eac0</ID>
        <Name>Livhuwani Nembilwi</Name>
        <ParentId>00000000-0000-0000-0000-000000000000</ParentId>
      </Value>
    </FieldValue>
    <FieldValue>
      <FieldID>GV_total__amount</FieldID>
      <Value xmlns:a="http://www.w3.org/2001/XMLSchema" i:type="a:decimal">1992943.771991</Value>
    </FieldValue>
    <FieldValue>
      <FieldID>GV_DW</FieldID>
      <Value xmlns:a="http://www.w3.org/2001/XMLSchema" i:type="a:string">DWPP2342</Value>
    </FieldValue>
    <FieldValue>
      <FieldID>GV_MDCEO</FieldID>
      <Value i:type="AssignToItem">
        <EntryType>User</EntryType>
        <ID>8cd8362e-31d3-4603-bf65-cbcb1484956a</ID>
        <Name>Mariam KANE-GARCIA</Name>
        <ParentId>00000000-0000-0000-0000-000000000000</ParentId>
      </Value>
    </FieldValue>
    <FieldValue>
      <FieldID>GV_division</FieldID>
      <Value xmlns:a="http://www.w3.org/2001/XMLSchema" i:type="a:string">Botswana</Value>
    </FieldValue>
    <FieldValue>
      <FieldID>GV_result</FieldID>
      <Value i:nil="true" />
    </FieldValue>
  </ContextProperties>
  <FaultedInfo i:nil="true" />
  <StopWorkflowInfo i:nil="true" />
  <UserCredentialsInfo i:nil="true" />
</InstanceXmlData>

理想情况下，我希望 TaskUser 的名称子节点中的值：“Hector THOLE”，但作为一种简单的调试方法，我尝试使用 FieldID：带有此查询的“GV_Divisional__Manager”：

 select XmlData.value('(/InstanceXmlData/ContextProperties/FieldValue/FieldID)[1]','varchar(max)') as 
 TaskUser
 from [dwworkflowengine].[dbo].[Instances]

结果是：

Query Results

我不确定为什么结果都是空的，非常感谢任何帮助。

Answer 1

您的 XML 文档中有一个默认的 XML 命名空间：

<InstanceXmlData xmlns="http://dev.docuware.com/bpw" xmlns:i="http://www.w3.org/2001/XMLSchema-instance">
                 ***********************************

但到目前为止，您完全忽略了它 - 不要那样做！

要获取 ID 元素的 Hector TOHLE 值，请使用以下 SQL：

-- define the default XML namespace to use
WITH XMLNAMESPACES(DEFAULT 'http://dev.docuware.com/bpw') 
    SELECT XmlData.value('(/InstanceXmlData/ContextProperties/FieldValue/Value/AssignToData/TaskUsers/TaskUser/ID)[1]', 'varchar(50)') 
    FROM [dwworkflowengine].[dbo].[Instances]
    WHERE XmlData.value('(/InstanceXmlData/ContextProperties/FieldValue/Value/AssignToData/TaskUsers/TaskUser/Name)[1]', 'varchar(50)') = 'Hector THOLE'