XPath expression

Question

I'm working on a DVWP where I'm trying to aggregate some data from a list based off some information in another list. I'm struggling to come up with the right XPath expression to do what I want.

In simple SQL terms, it be select * from requests where labid in (select labid from labs where dataowner = currentuser)

My dsQueryResponse looks like this:

dsQueryResponse -
Labs - Rows - Row - LabId, Data Owner
Requests - Rows -LabID, other fields

What would the XPath filter look like for that? I'm struggling trying to get the collection of labs from the Lab list where the data owner would be the current user, then using those lab ids to return all the requests from those Labs.

The Lab dsQueryResponse looks like this (sanitized some). Requests is in similar output.

<Row Title="1" LabID="1" Room="none" Lab_x0020_Location="Warehouse" Lab_x0020_Contact="Pirate Eric" Lab_x0020_Phone="555-9543" Lab_x0020_Hours="[M-F] 8-5|Sa-Su Closed" LabStatsID="" Lab_x0020_Status="Inactive" 
    ContentType="Computer Lab" Data_x0020_Owner="Alexander, Eric" NewLabVe="" UpdateLa="5" Building="No Physical Location" LabType="N" SpecialNeeds="N" OldLabID="" College="Academic Support" Department="Academic Support" 
    Department_x0020_Head="Our Boss" Department_x0020_Head_x0020_Emai="user@place.com" ID="1" Modified="2011-04-25T13:19:28Z" Created="2010-09-28T17:53:49Z" Author="Alexander, Eric" 
    Editor="Alexander, Eric" _UIVersionString="1.0" Attachments="0" LinkTitleNoMenu="1" LinkTitle="1" FileRef="" FileDirRef="" FSObjType="0" ProgId="" ScopeId="{68FB6470-C1B0-419E-B668-FC4FB7E3C4CF}" DocIcon="" MetaInfo="vti_encoding:SR|utf8-nl
WorkflowCreationPath:SW|d6bda0a0-646d-4e70-ba11-da9956f380c2,19;"/>

Answer 1

If your XML is structured like your file structure try this:

/dsQueryResponse/Requests/Rows[ LabID=/dsQueryResponse/Labs/Rows/Row[DataOwner='Abe Miessler']/LabID ]

I am assuming that you have a LabID under Rows that was just left out of the screen shot.

UPDATE:

I tested it with the following XML and it appeared to work:

<dsQueryResponse>
 <Labs>
  <Rows>
    <Row>
      <LabID>1</LabID>
      <DataOwner>Abe Miessler</DataOwner>
    </Row>
  </Rows>
 </Labs>
 <Requests>
  <Rows>
   <LabID>1</LabID>
   <PrinterModel>blah</PrinterModel>
  </Rows>
  <Rows>
   <LabID>1</LabID>
   <PrinterModel>blah 2</PrinterModel>
  </Rows>
  <Rows>
   <LabID>2</LabID>
   <PrinterModel>blah3333</PrinterModel>
  </Rows>
 </Requests>
</dsQueryResponse>

Answer 2

After a lot of trial and error and a lot of help from Marc Anderson, we finally got this sorted out. The actual Rows expression I needed was,

<xsl:variable name="Rows" select="/dsQueryResponse/Labs/Rows/Row[substring-after(substring-before(substring-after(@Data_x0020_Owner, 'ID='), '&lt;'), '&gt;') = $UserID]" />

I'm returning a filtered list of labs the current user owns, then using a joined subview to show all the associated requests for that lab. Thanks for the help Abe, I appreciate it.