Compare data of 2 xmls in xslt - xslt

Question

I am new to XSL. Hence please help me with the below.
I have 2 xmls. I have to do the following in XSL transformation.
if Employee/EmployeeInfo/FirstName = EmployeeSegment/EmployeeSummary/GivenName and Employee/EmployeeInfo/LastName = EmployeeSegment/EmployeeSummary/Surname
employeeId = EmployeeSegment/EmployeeSummary/EmpId
XML1
<Employee>
<EmployeeInfo>
<FirstName>ABC</FirstName>
<LastName>DEF</LastName>
</EmployeeInfo>
</Employee>
XML2
<EmployeeSegment>
<EmployeeSummary>
<EmpId>1234</EmpId>
<GivenName>ABC</GivenName>
<Surname>DEF</Surname>
</EmployeeSummary>
</EmployeeSegment>
I have tried the following. It is not working.
<xsl:param name="cjEmployeeSegment" select="document('CJ_Response.xml')"/>
<xsl:for-each select="/ns3:Employee/ns3:EmployeeInfo">
<xsl:variable name="empFirstName">
<xsl:value-of select="ns1:FirstName"/>
</xsl:variable>
<xsl:variable name="empLastName">
<xsl:value-of select="ns1:LastName"/>
</xsl:variable>
<xsl:for-each select="$cjEmployeeSegment/v32:EmployeeSegment/v31:EmployeeSummary">
<xsl:if test="$empFirstName=v31:GivenName and $empLastName=v31:Surname">
<ns12:EmployeeIdentifier>
<ns12:EmployeeID>
<xsl:value-of select="v31:EmpId"/>
</ns12:EmployeeID>
</ns12:EmployeeIdentifier>
</xsl:if>
</xsl:for-each>
</xsl:for-each>

Answer 1

Assuming you are processing the following input:
XML
<Employee>
<EmployeeInfo>
<FirstName>ABC</FirstName>
<LastName>DEF</LastName>
</EmployeeInfo>
</Employee>
and there is another XML document named CJ_Response.xml:
<EmployeeSegment>
<EmployeeSummary>
<EmpId>1234</EmpId>
<GivenName>ABC</GivenName>
<Surname>DEF</Surname>
</EmployeeSummary>
</EmployeeSegment>
you can use the following stylesheet:
XSLT 1.0
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:param name="cj_Response" select="document('CJ_Response.xml')"/>
<xsl:template match="/Employee">
<root>
<xsl:for-each select="EmployeeInfo">
<xsl:variable name="lookup" select="$cj_Response/EmployeeSegment/EmployeeSummary[GivenName = current()/FirstName and Surname = current()/LastName]" />
<xsl:if test="$lookup">
<EmployeeIdentifier>
<EmployeeID>
<xsl:value-of select="$lookup/EmpId"/>
</EmployeeID>
</EmployeeIdentifier>
</xsl:if>
</xsl:for-each>
</root>
</xsl:template>
</xsl:stylesheet>
to return:
<?xml version="1.0" encoding="UTF-8"?>
<root>
<EmployeeIdentifier>
<EmployeeID>1234</EmployeeID>
</EmployeeIdentifier>
</root>
Of course, this will fail miserably if there are two or more employees with the same name.