Re: Grouping using concatenated key

> Does this clarify things?

yes.

change match="/" to match="NewDataset"



<NewDataset>
  <BillDetail>
    <OBLIGATION_ID>2750</OBLIGATION_ID>
    <PHONE_NUMBER>1234567890</PHONE_NUMBER>
    <one/>
  </BillDetail>
  <BillDetail>
    <OBLIGATION_ID>2750</OBLIGATION_ID>
    <PHONE_NUMBER>1234567890</PHONE_NUMBER>
    <two/>
  </BillDetail>
  <BillDetail>
    <OBLIGATION_ID>2750</OBLIGATION_ID>
    <PHONE_NUMBER>9876543210</PHONE_NUMBER>
  </BillDetail>
  <BillDetail>
    <OBLIGATION_ID>3940</OBLIGATION_ID>
    <PHONE_NUMBER>1234567890</PHONE_NUMBER>
  </BillDetail>
</NewDataset>



<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">

<xsl:key name="byObligation" match="BillDetail" use="OBLIGATION_ID" />
<xsl:key name="byObligationAndPhone" match="BillDetail"
use="concat(OBLIGATION_ID, ':',PHONE_NUMBER)" />

<xsl:strip-space elements="*"/>
<xsl:output indent="yes"/>

<xsl:template match="NewDataset">
  <xsl:for-each select="BillDetail[generate-id()=generate-id(key('byObligation',OBLIGATION_ID))]">
    <xsl:variable name="OBLIGATION" select="OBLIGATION_ID"/>
    <group>
      <xsl:for-each
	  select="../BillDetail[generate-id()=generate-id(key('byObligationAndPhone'
		  ,concat($OBLIGATION,':',PHONE_NUMBER)))]">
	<group>
	  <xsl:copy-of select="key('byObligationAndPhone' ,concat($OBLIGATION,':',PHONE_NUMBER))"/>
	</group>
      </xsl:for-each>
    </group>
  </xsl:for-each>
</xsl:template>

</xsl:stylesheet>




saxon nds.xml nds.xsl
<?xml version="1.0" encoding="utf-8"?>
<group>
   <group>
      <BillDetail>
         <OBLIGATION_ID>2750</OBLIGATION_ID>
         <PHONE_NUMBER>1234567890</PHONE_NUMBER>
         <one/>
      </BillDetail>
      <BillDetail>
         <OBLIGATION_ID>2750</OBLIGATION_ID>
         <PHONE_NUMBER>1234567890</PHONE_NUMBER>
         <two/>
      </BillDetail>
   </group>
   <group>
      <BillDetail>
         <OBLIGATION_ID>2750</OBLIGATION_ID>
         <PHONE_NUMBER>9876543210</PHONE_NUMBER>
      </BillDetail>
   </group>
</group>
<group>
   <group>
      <BillDetail>
         <OBLIGATION_ID>3940</OBLIGATION_ID>
         <PHONE_NUMBER>1234567890</PHONE_NUMBER>
      </BillDetail>
   </group>
</group>