Merging two diff XMLS using XSLT(1.0) - xslt

Question

I am new to XSLT and I need help in merging two different XML documents into one.
XML1.xml
<customers>
<customer>
<Person name="Ram" Id="101"/>
<address>flat 4</address>
</customer>
<customer>
<Person name="Raghav" Id="102"/>
<address>flat 9</address>
</customer>
</customers>
XML2.xml
<Products>
<Product>
<name>Onida Tv</name>
<consumer>Ram</consumer>
</Product>
<Product>
<name>washing machine</name>
<consumer>Ram</consumer>
</Product>
<Product>
<name>Water purifier</name>
<consumer>Raghav</consumer>
</Product>
<Product>
<name>iPhone</name>
<consumer>Raghav</consumer>
</Products>
</Products>
Desired XML output:
<customers>
<customer>
<Person name="Ram" Id="101"/>
<address>flat 4</address>
<products>
<name>washing machine</name>
<name>Onida TV</name>
</products>
</customer>
<customer>
<Person name="Raghav" Id="102"/>
<address>flat 9</address>
<products>
<name>iPhone</name>
<name>Water purifier</name>
</products>
</customer>
</customers>
The second XML is to be considered external in this context. I need to append to each customer the corresponding products. How can I do that?

Answer 1

Try it this way:
XSLT 1.0
<?xml version="1.0" encoding="UTF-8"?>
<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:strip-space elements="*"/>
<xsl:variable name="lookup-document" select="document('XML2.xml')" />
<xsl:key name="product-by-consumer" match="Product" use="consumer" />
<!-- identity transform -->
<xsl:template match="#*|node()">
<xsl:copy>
<xsl:apply-templates select="#*|node()"/>
</xsl:copy>
</xsl:template>
<xsl:template match="customer">
<xsl:copy>
<xsl:apply-templates select="#*|node()"/>
<xsl:variable name="name" select="Person/#name" />
<products>
<!-- switch context to the other document in order to use key -->
<xsl:for-each select="$lookup-document">
<xsl:copy-of select="key('product-by-consumer', $name)/name"/>
</xsl:for-each>
</products>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>
Note that this assumes that customer names are unique.