i am trying to write an XSLT which will group all relevant SG9 segment based on SG9 field A_51 where A_50= KAR (xpath: INVR/SG9/SG11/SG14/FFR/C506[A_50='KAR']/A_51 in input xml), after grouping for each group we need to add <TNU>segment in the last, my xslt is not giving exact result, Please check once
Input sample
<?xml version="1.0" encoding="UTF-8"?>
<INVR>
<HNU_S>
<FIELD1>0002</FIELD1>
</HNU_S>
<MGB_S>
<FIELD1>2410458</FIELD1>
</MGB_S>
<GS2>
<NODE>
<FIELD2>SU</FIELD2>
</NODE>
</GS2>
<SG9>
<NIL_S>
<FIELD1>4141</FIELD1>
</NIL_S>
<SG11>
<SG14>
<FFR>
<C506>
<A_50>KAR</A_50>
<A_51>1234</A_51>
</C506>
</FFR>
</SG14>
</SG11>
</SG9>
<SG9>
<NIL_S>
<FIELD1>43636</FIELD1>
</NIL_S>
<SG11>
<SG14>
<FFR>
<C506>
<A_50>KAR</A_50>
<A_51>4567</A_51>
</C506>
</FFR>
</SG14>
</SG11>
</SG9>
<SG9>
<NIL_S>
<FIELD1>65757</FIELD1>
</NIL_S>
<SG11>
<SG14>
<FFR>
<C506>
<A_50>KKR</A_50>
<A_51>1234</A_51>
</C506>
</FFR>
</SG14>
</SG11>
</SG9>
<SG9>
<NIL_S>
<FIELD1>14145</FIELD1>
</NIL_S>
<SG11>
<SG14>
<FFR>
<C506>
<A_50>KKR</A_50>
<A_51>4567</A_51>
</C506>
</FFR>
</SG14>
</SG11>
</SG9>
<TNU>
<FIELD1>330</FIELD1>
</TNU>
</INVR>
output sample
<?xml version="1.0" encoding="UTF-8"?>
<INVR>
<HNU_S>
<FIELD1>0002</FIELD1>
</HNU_S>
<MGB_S>
<FIELD1>2410458</FIELD1>
</MGB_S>
<GS2>
<NODE>
<FIELD2>SU</FIELD2>
</NODE>
</GS2>
<group>
<SG9>
<NIL_S>
<FIELD1>4141</FIELD1>
</NIL_S>
<SG11>
<SG14>
<FFR>
<C506>
<A_50>KAR</A_50>
<A_51>1234</A_51>
</C506>
</FFR>
</SG14>
</SG11>
</SG9>
<SG9>
<NIL_S>
<FIELD1>65757</FIELD1>
</NIL_S>
<SG11>
<SG14>
<FFR>
<C506>
<A_50>KKR</A_50>
<A_51>1234</A_51>
</C506>
</FFR>
</SG14>
</SG11>
</SG9>
<TNU>
<FIELD1>330</FIELD1>
</TNU>
</group>
<group>
<SG9>
<NIL_S>
<FIELD1>43636</FIELD1>
</NIL_S>
<SG11>
<SG14>
<FFR>
<C506>
<A_50>KAR</A_50>
<A_51>4567</A_51>
</C506>
</FFR>
</SG14>
</SG11>
</SG9>
<SG9>
<NIL_S>
<FIELD1>14145</FIELD1>
</NIL_S>
<SG11>
<SG14>
<FFR>
<C506>
<A_50>KKR</A_50>
<A_51>4567</A_51>
</C506>
</FFR>
</SG14>
</SG11>
</SG9>
<TNU>
<FIELD1>330</FIELD1>
</TNU>
</group>
</INVR>
XSLT I used
<xsl:stylesheet xmlns:xsl="
http://www.w3.org/1999/XSL/Transform" version="2.0">
<xsl:output method="xml" indent="yes"/>
<xsl:template match="@*|node()">
<xsl:copy>
<xsl:apply-templates select="@*|node()"/>
</xsl:copy>
</xsl:template>
<xsl:template match="SG9">
<G_SG9>
<xsl:apply-templates select="*[not(self::SG9)]"/>
<xsl:for-each-group select="SG9" group-by="/INVR/SG9/SG11/SG14/FFR/C506[A_50='KAR']/A_51">
<group>
<xsl:copy-of select="current-group()"/>
</group>
</xsl:for-each-group>
</G_SG9>
</xsl:template>
</xsl:stylesheet>
If I understand correctly what you are looking to do, then I think you would create an empty template for SG9 and then have a template matching on TNU that selects and groups the SG9 elements and emits the TNU at the end of each group:
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="2.0">
<xsl:output method="xml" indent="yes"/>
<xsl:template match="@*|node()">
<xsl:copy>
<xsl:apply-templates select="@*|node()"/>
</xsl:copy>
</xsl:template>
<xsl:template match="SG9"/>
<xsl:template match="TNU">
<xsl:variable name="TNU" select="."/>
<xsl:for-each-group select="/INVR/SG9" group-by="SG11/SG14/FFR/C506/A_51">
<group>
<xsl:copy-of select="current-group()"/>
<xsl:copy-of select="$TNU"/>
</group>
</xsl:for-each-group>
</xsl:template>
</xsl:stylesheet>
Which produces the following output:
<INVR>
<HNU_S>
<FIELD1>0002</FIELD1>
</HNU_S>
<MGB_S>
<FIELD1>2410458</FIELD1>
</MGB_S>
<GS2>
<NODE>
<FIELD2>SU</FIELD2>
</NODE>
</GS2>
<group>
<SG9>
<NIL_S>
<FIELD1>4141</FIELD1>
</NIL_S>
<SG11>
<SG14>
<FFR>
<C506>
<A_50>KAR</A_50>
<A_51>1234</A_51>
</C506>
</FFR>
</SG14>
</SG11>
</SG9>
<SG9>
<NIL_S>
<FIELD1>65757</FIELD1>
</NIL_S>
<SG11>
<SG14>
<FFR>
<C506>
<A_50>KKR</A_50>
<A_51>1234</A_51>
</C506>
</FFR>
</SG14>
</SG11>
</SG9>
<TNU>
<FIELD1>330</FIELD1>
</TNU>
</group>
<group>
<SG9>
<NIL_S>
<FIELD1>43636</FIELD1>
</NIL_S>
<SG11>
<SG14>
<FFR>
<C506>
<A_50>KAR</A_50>
<A_51>4567</A_51>
</C506>
</FFR>
</SG14>
</SG11>
</SG9>
<SG9>
<NIL_S>
<FIELD1>14145</FIELD1>
</NIL_S>
<SG11>
<SG14>
<FFR>
<C506>
<A_50>KKR</A_50>
<A_51>4567</A_51>
</C506>
</FFR>
</SG14>
</SG11>
</SG9>
<TNU>
<FIELD1>330</FIELD1>
</TNU>
</group>
</INVR>