xslt - Find maximum value of all child elements and only get the max row of that child using xsl transformation 1.0 -

for example source xml

<records>     <record>         <personid>111</personid>         <location>australia</location>         <year>1999</year>     </record>     <record>         <personid>222</personid>         <location>netherland</location>         <year>1919</year>     </record>     <record>         <personid>111</personid>         <location>usa</location>         <year>2000</year>     </record> </records> 

now after xsl should below takes latest year's (max on elemtnt year) , discards old records personid:

<records>     <record>         <personid>222</personid>         <location>netherland</location>         <year>1919</year>     </record>     <record>         <personid>111</personid>         <location>usa</location>         <year>2000</year>     </record> </records> 

this stylesheet:

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/xsl/transform">     <xsl:key name="krecordbypersonid" match="record" use="personid"/>     <xsl:template match="node()|@*" name="identity">         <xsl:copy>             <xsl:apply-templates select="node()|@*"/>         </xsl:copy>     </xsl:template>     <xsl:template match="record"/>     <xsl:template match="record[count(.|key('krecordbypersonid',personid)[1])                                  = 1]">         <xsl:for-each select="key('krecordbypersonid',personid)">             <xsl:sort select="year" data-type="number" order="descending"/>             <xsl:if test="position()=1">                 <xsl:call-template name="identity"/>             </xsl:if>         </xsl:for-each>     </xsl:template> </xsl:stylesheet> 

output:

<records>     <record>         <personid>111</personid>         <location>usa</location>         <year>2000</year>     </record>     <record>         <personid>222</personid>         <location>netherland</location>         <year>1919</year>     </record> </records> 

just fun, preserving input source order performance:

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/xsl/transform">     <xsl:key name="krecordbypersonid" match="record" use="personid"/>     <xsl:template match="node()|@*" name="identity">         <xsl:copy>             <xsl:apply-templates select="node()|@*"/>         </xsl:copy>     </xsl:template>     <xsl:template match="records">         <xsl:copy>             <xsl:apply-templates select="@*"/>             <xsl:call-template name="group-max">                 <xsl:with-param name="pgroup"                  select="record[count(.|key('krecordbypersonid',personid)[1])                                  = 1]"/>             </xsl:call-template>         </xsl:copy>     </xsl:template>     <xsl:template name="group-max">         <xsl:param name="pgroup" select="/.."/>         <xsl:param name="pgroup-max" select="/.."/>         <xsl:choose>             <xsl:when test="$pgroup">                 <xsl:for-each                  select="key('krecordbypersonid',$pgroup[1]/personid)">                     <xsl:sort select="year"                               data-type="number"                               order="descending"/>                     <xsl:if test="position()=1">                         <xsl:call-template name="group-max">                             <xsl:with-param name="pgroup"                              select="$pgroup[position()!=1]"/>                             <xsl:with-param name="pgroup-max"                              select="$pgroup-max|."/>                         </xsl:call-template>                     </xsl:if>                 </xsl:for-each>             </xsl:when>             <xsl:otherwise>                 <xsl:apply-templates select="$pgroup-max"/>             </xsl:otherwise>         </xsl:choose>     </xsl:template> </xsl:stylesheet> 

output:

<records>     <record>         <personid>222</personid>         <location>netherland</location>         <year>1919</year>     </record>     <record>         <personid>111</personid>         <location>usa</location>         <year>2000</year>     </record> </records>