Combining two xml files - xslt

Question

I want to combine two xsl files into one. I tried but I am failing to do so. Both of these xsl files work fine separately but when I combine them, it does not. I am not expert in xsl.
Here is the first xsl file:
<xsl:variable name="products" select="document('T01_product.xml')/products"/>
<xsl:strip-space elements="*"/>
<xsl:key name="product" match="product" use="pm-id" />
<!-- identity transform -->
<xsl:template match="#*|node()">
<xsl:copy>
<xsl:apply-templates select="#*|node()"/>
</xsl:copy>
</xsl:template>
<xsl:template match="deleted-assignment/pm-id">
<xsl:copy-of select="."/>
<xsl:copy-of select="key('product', .)/art-num"/>
</xsl:template>
</xsl:stylesheet>
second xsl file is
<xsl:variable name="items" select="document('T01_item.xml')/items"/>
<xsl:strip-space elements="*"/>
<xsl:key name="item" match="item" use="pm-id" />
<!-- identity transform -->
<xsl:template match="#*|node()">
<xsl:copy>
<xsl:apply-templates select="#*|node()"/>
</xsl:copy>
</xsl:template>
<xsl:template match="deleted-assignment/pm-id">
<xsl:copy-of select="."/>
<xsl:copy-of select="key('item', .)/art-num"/>
</xsl:template>
</xsl:stylesheet>
Thanks in advance

Answer 1

When you say you want to combine two stylesheets A and B, do you mean that you first want to apply transformation A, and then apply transformation B to the result? If that's what you want, then it might be better to keep them separate, and use some pipelining technology to organize the work flow (e.g. XProc but there are many other candidates).
It's also possible to do a single-stylesheet pipeline, especially in XSLT 2.0, using modes: put all the rules for each transformation into a separate mode, capture the result of each phase in a variable, and then apply-templates to the variable specifying the mode-name for the next phase.
If you want to combine the stylesheets in some other way, then you need to explain the requirement better.

Answer 2

You have not explained how your input looks and which result you want so this is a wild guess, perhaps you want to combine
<xsl:template match="deleted-assignment/pm-id">
<xsl:copy-of select="."/>
<xsl:copy-of select="key('product', .)/art-num"/>
</xsl:template>
and
<xsl:template match="deleted-assignment/pm-id">
<xsl:copy-of select="."/>
<xsl:copy-of select="key('item', .)/art-num"/>
</xsl:template>
to
<xsl:template match="deleted-assignment/pm-id">
<xsl:copy-of select="."/>
<xsl:copy-of select="key('product', .)/art-num"/>
<xsl:copy-of select="key('item', .)/art-num"/>
</xsl:template>