Untitled

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
      <xsl:output method="xml" indent="yes"/>

    <xsl:key name="lookup" match="/S5Data/ZasobaList/Zasoba/Kod" use="." />
    
    <xsl:template match="/">
        <S5Data>
            <ZasobaList>
                <xsl:for-each select="S5Data/ZasobaList/Zasoba/Kod[generate-id(.) = generate-id(key('lookup',.)[1])]">
                    <Kod>
                        <xsl:value-of select="."/>
                    </Kod>
                    <xsl:for-each select="key('lookup',.)">
                        <xsl:for-each select="ancestor::Zasoba/Detaily/ZasobaDetail/Mnozstvi">
                            <Stav>
                                <xsl:value-of select="."/>
                          </Stav>
                        </xsl:for-each>              
                          </xsl:for-each>
                          <sum><xsl:value-of select="sum(ancestor::Zasoba/Detaily/ZasobaDetail/Mnozstvi)"></xsl:value-of></sum>
                         </xsl:for-each>
            </ZasobaList>
        </S5Data>
    </xsl:template>
</xsl:stylesheet>



RESULT:
<?xml version="1.0" encoding="utf-8"?>
<S5Data>
  <ZasobaList>
    <Kod>P046</Kod>
    <Stav>2087.6000</Stav>
    <Stav>32847.2000</Stav>
    <sum>2087.6</sum>
    <Kod>RZP06</Kod>
    <Stav>2.0000</Stav>
    <Stav>0.0000</Stav>
    <Stav>0.0000</Stav>
    <sum>2</sum>
  </ZasobaList>
</S5Data>