Sorting in xslt and choosing minimum or maximum va

Question

Need some help in sorting and then choosing either maximum or minimum value in XSLT.

Source xml:

<target>
<relatedTarget>
<permitExpiry>2005-07-02T08:11:00.000Z</permitExpiry>
<permitStart>2015-07-11T09:22:00.000Z</permitStart>
</relatedTarget>

<relatedTarget>
<permitExpiry>2003-07-12T08:11:00.000Z</permitExpiry>
<permitStart>2014-07-01T09:22:00.000Z</permitStart>
</relatedTarget>

<relatedTarget>
<permitExpiry>2002-07-10T08:11:00.000Z</permitExpiry>
<permitStart>2016-07-06T09:22:00.000Z</permitStart>
</relatedTarget>
</target>

Result xml:

<target>
<relatedTarget>
<permitStart>2014-07-01T09:22:00.000Z</permitStart>
<permitExpiry>2005-07-02T08:11:00.000Z</permitExpiry>
</relatedTarget>
</target>

Basically i need the result should have minimum permitStart date and maximum permitExpiry date from among all the dates comming.

My sample xsl:

<xsl:template match="/">


<xsl:variable name="permitStartVar" select="//permitStart"/>        
<xsl:variable name="permitStopVar" select="//permitExpiry"/>        

<xsl:for-each select="relatedTask">     
<xsl:sort select="substring(permitStart,1,4)" /> <!-- Year -->
<xsl:sort select="substring(permitStart,6,2)" /> <!-- Month -->
<xsl:sort select="substring(permitStart,9,2)" /> <!-- Day -->
<xsl:sort select="substring(permitStart,12,2)" /> <!-- Hour -->
<xsl:sort select="substring(permitStart,15,2)" /> <!-- Minute -->
<xsl:sort select="substring(permitStart,18,2)" /> <!-- Second -->


<xsl:sort select="substring(permitExpiry,1,4)" /> <!-- Year -->
<xsl:sort select="substring(permitExpiry,6,2)" /> <!-- Month -->
<xsl:sort select="substring(permitExpiry,9,2)" /> <!-- Day -->
<xsl:sort select="substring(permitExpiry,12,2)" /> <!-- Hour -->
<xsl:sort select="substring(permitExpiry,15,2)" /> <!-- Minute -->
<xsl:sort select="substring(permitExpiry,18,2)" /> <!-- Second --> 
</xsl:for-each>

<target>
<relatedTarget>
<permitStart><xsl:value-of select="$permitStartVar[1]"/></permitStart>
<permitExpiry><xsl:value-of select="$permitStopVar[last()]"/></permitExpiry>
</relatedTarget>    
</target>

</template>

Answer 1

As I follow your approach ,

<xsl:stylesheet exclude-result-prefixes="xs" version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xsl:template match="target">
  <xsl:variable name="permitStartVar" select="//permitStart"/>
  <xsl:variable name="permitStopVar" select="//permitExpiry"/>
  <xsl:variable name="temp">
     <xsl:for-each select="relatedTarget/permitStart">
        <xsl:sort select="substring(permitStart,1,4)"/>
        <!--Year-->
        <xsl:sort select="substring(permitStart,6,2)"/>
        <!--Month-->
        <xsl:sort select="substring(permitStart,9,2)"/>
        <!--Day-->
        <xsl:sort select="substring(permitStart,12,2)"/>            <!--Hour-->
        <xsl:sort select="substring(permitStart,15,2)"/>
        <!--Minute-->
        <xsl:sort select="substring(permitStart,18,2)"/>
        <!--Second-->
        <xsl:copy-of select="."/>
     </xsl:for-each>
  </xsl:variable>
  <xsl:variable name="temp1">
     <xsl:for-each select="relatedTarget/permitExpiry">
        <xsl:sort select="substring(permitExpiry,1,4)" order="descending"/>
        <!--Year-->
        <xsl:sort select="substring(permitExpiry,6,2)" order="descending"/>
        <!--Month-->
        <xsl:sort select="substring(permitExpiry,9,2)" order="descending"/>
        <!--Day-->
        <xsl:sort select="substring(permitExpiry,12,2)" order="descending"/>
        <!--Hour-->
        <xsl:sort select="substring(permitExpiry,15,2)" order="descending"/>
        <!--Minute-->
        <xsl:sort select="substring(permitExpiry,18,2)" order="descending"/>
        <!--Second-->
        <xsl:copy-of select="."/>
     </xsl:for-each>
  </xsl:variable>
  <target>
     <relatedTarget>
        <permitStart>
           <xsl:value-of select="$temp//permitStart[1]"/>
        </permitStart>
        <permitExpiry>
           <xsl:value-of select="$temp1/permitExpiry[1]"/>
        </permitExpiry>
     </relatedTarget>
  </target>
 </xsl:template>
 </xsl:stylesheet>

Output :

<target>
<relatedTarget>
  <permitStart>2014-07-01T09:22:00.000Z</permitStart>
  <permitExpiry>2003-07-12T08:11:00.000Z</permitExpiry>
</relatedTarget>
</target>

EDIT :

More simplified version :

<xsl:stylesheet exclude-result-prefixes="xs" version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xsl:template match="target">
  <xsl:variable name="permitStartVar" select="//permitStart"/>
  <xsl:variable name="permitStopVar" select="//permitExpiry"/>

  <xsl:variable name="temp">
     <xsl:for-each select="relatedTarget/permitStart">
        <xsl:sort select="."/>
        <xsl:copy-of select="."/>
     </xsl:for-each>
  </xsl:variable>
  <xsl:variable name="temp1">
     <xsl:for-each select="relatedTarget/permitExpiry">
        <xsl:sort select="."  order="descending"/>
        <xsl:copy-of select="."/>
     </xsl:for-each>
  </xsl:variable>
  <target>
     <relatedTarget>
        <permitStart>
           <xsl:value-of select="$temp//permitStart[1]"/>
        </permitStart>
        <permitExpiry>
           <xsl:value-of select="$temp1/permitExpiry[1]"/>
        </permitExpiry>
     </relatedTarget>
  </target>
</xsl:template>
</xsl:stylesheet>

Answer 2

You could do this without sorting by using max() and min() on the xs:dateTime values.

Example

XML Input

<target>
    <relatedTarget>
        <permitExpiry>2005-07-02T08:11:00.000Z</permitExpiry>
        <permitStart>2015-07-11T09:22:00.000Z</permitStart>
    </relatedTarget>

    <relatedTarget>
        <permitExpiry>2003-07-12T08:11:00.000Z</permitExpiry>
        <permitStart>2014-07-01T09:22:00.000Z</permitStart>
    </relatedTarget>

    <relatedTarget>
        <permitExpiry>2002-07-10T08:11:00.000Z</permitExpiry>
        <permitStart>2016-07-06T09:22:00.000Z</permitStart>
    </relatedTarget>
</target>

XSLT 2.0

<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" 
    xmlns:xs="http://www.w3.org/2001/XMLSchema" 
    exclude-result-prefixes="xs">
    <xsl:output indent="yes"/>
    <xsl:strip-space elements="*"/>

    <xsl:template match="/*">
        <target>
            <relatedTarget>
                <xsl:copy-of select="(relatedTarget/permitStart[.=min(/*/relatedTarget/xs:dateTime(permitStart))])[1]"/>
                <xsl:copy-of select="(relatedTarget/permitExpiry[.=max(/*/relatedTarget/xs:dateTime(permitExpiry))])[1]"/>
            </relatedTarget>
        </target>
    </xsl:template>

</xsl:stylesheet>

Output

<target>
   <relatedTarget>
      <permitStart>2014-07-01T09:22:00.000Z</permitStart>
      <permitExpiry>2005-07-02T08:11:00.000Z</permitExpiry>
   </relatedTarget>
</target>