how to select preceding nodes within a specific parent - xslt-1.0

Question

Given the following xml
<Root>
<Employee>
<service>
<Record>xxx</Record>
<Record>yyy</Record>
</service>
<service>
<Record>xxx</Record>
<Record>yyy</Record>
<Record>zzz</Record>
</service>
</Employee>
<Employee>
<service>
<Record>xxx</Record>
<Record>yyy</Record>
</service>
<service>
<Record>xxx</Record>
<Record>yyy</Record>
<Record>zzz</Record>
</service>
</Employee>
</Root>
Using XSLT1.0, while transforming the xml for each <Employee> the <Record> field containing 'xxx','yyy','zzz' should occur only once in the result
<Root>
<Employee>
<Service>
<Record>xxx</Record>
<Record>yyy</Record>
<Record>zzz</Record>
</Service>
</Employee>
<Employee>
<Service>
<Record>xxx</Record>
<Record>yyy</Record>
<Record>zzz</Record>
<Service>
</Employee>
</Root>
In a for-each loop of Employee I tired using <xsl:if test='not(preceding::./service/Record=$record)'>. The test works fine for the first <Employee> taking the <Record> for 'xxx','yyy','zzz' only once. When the iteration goes to the next <Employee> the test condition checks for the <Record>values in the first<Employee> also and it finds preceding nodes already exisitng with the values'xxx','yyy','zzz', hence i am not able to get the records for the second <Employee>.
How to get the <Record>s in the second <Employee> . Any help is much appreciated.
Thanks

Answer 1

This transformation uses the Muenchian method for grouping:
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:strip-space elements="*"/>
<xsl:key name="kEmpRecordByVal" match="Employee/service/Record"
use="concat(generate-id(../..), '+', .)"/>
<xsl:template match="node()|#*">
<xsl:copy>
<xsl:apply-templates select="node()|#*"/>
</xsl:copy>
</xsl:template>
<xsl:template match="Employee">
<Employee>
<xsl:apply-templates select=
"service/Record
[generate-id()
=
generate-id(key('kEmpRecordByVal',
concat(generate-id(../..), '+', .)
)[1]
)
]
"/>
</Employee>
</xsl:template>
</xsl:stylesheet>
when applied on the following XML document (the provided one with different values for the second Employee to aid readability):
<Root>
<Employee>
<service>
<Record>xxx</Record>
<Record>yyy</Record>
</service>
<service>
<Record>xxx</Record>
<Record>yyy</Record>
<Record>zzz</Record>
</service>
</Employee>
<Employee>
<service>
<Record>aaa</Record>
<Record>bbb</Record>
</service>
<service>
<Record>aaa</Record>
<Record>bbb</Record>
<Record>ccc</Record>
</service>
</Employee>
</Root>
the wanted, correct result is produced:
<Root>
<Employee>
<Record>xxx</Record>
<Record>yyy</Record>
<Record>zzz</Record>
</Employee>
<Employee>
<Record>aaa</Record>
<Record>bbb</Record>
<Record>ccc</Record>
</Employee>
</Root>