Thanks for posting a clear example, that always helps. In future it also
helps to say if you want xslt 2 or xslt 1, in this case it wouldn't make
much difference, but in other cases it can make a lot....

Basically you want to set up a key to handle the association
of artists and titles.

David


<xsl:stylesheet  version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
 
<xsl:output indent="yes"/>
<xsl:strip-space elements="*"/>

<xsl:template match="Catalog">
 <Catalog>
 <xsl:apply-templates select="cds/cd"/>
 </Catalog>
</xsl:template>

<xsl:template match="cd">
 <cd>
  <xsl:copy-of select="title"/>
  <artist><xsl:value-of select="key('artist',number)/name"/></artist>
 </cd>
</xsl:template>

<xsl:key name="artist" match="artist" use="number"/>

</xsl:stylesheet>



produces


$ saxon cata.xml cata.xsl
<?xml version="1.0" encoding="utf-8"?>
<Catalog>
   <cd>
      <title>Empire Burlesque</title>
      <artist>Bob Dylan</artist>
   </cd>
   <cd>
      <title>Hide Your Heart</title>
      <artist>Bonnie Tyler</artist>
   </cd>
</Catalog>




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