Hello

I'm trying to obtain the distinct values given a combination of nodes (Company and Location). I have created a XSLT (see below) that uses for-each-group, however I always obtain two instances of the first combination in the results.

This is the the sample XML:

<ns0:ClientList xmlns:ns0="http://Test">
    <DataList>
        <Company>60</Company>
        <Location>02</Location>
    </DataList>
    <DataList>
        <Company>60</Company>
        <Location>01</Location>
    </DataList>
    <DataList>
        <Company>60</Company>
        <Location>03</Location>
    </DataList>
</ns0:ClientList>


I'm using the XSLT below:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:fn="http://www.w3.org/2005/xpath-functions" xmlns:xdt="http://www.w3.org/2005/xpath-datatypes">
    <xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>


    <xsl:template match="/">

<xsl:for-each-group select="//DataList" group-by="Company|Location" >
            <xsl:element name="Company">
                <xsl:value-of select="Company|Location"/>
            </xsl:element>
            <xsl:element name="Location">
                <xsl:value-of select="Location"/>
            </xsl:element>
</xsl:for-each-group>

    </xsl:template>
</xsl:stylesheet>



These are the result I'm getting:

<?xml version="1.0" encoding="UTF-8"?>
<Company>60 02</Company>
<Location>02</Location>
<Company>60 02</Company>
<Location>02</Location>
<Company>60 01</Company>
<Location>01</Location>
<Company>60 03</Company>
<Location>03</Location>

When group-by selects a sequence of several items, then each value in the sequence is considered to form a grouping key in its own right, and the relevant node ends up in more than one group. The use case for this is grouping books by author - if a book has several authors, it goes in each of the author groups.

To group on a composite key, you have a choice. You can form the grouping key as a concatenation: group-by="concat(Company, '|', Location)". Or you can use two nested groupings:

<xsl:for-each-group ... group-by="Company">
  <xsl:for-each-group ... group-by="Location">

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference