Split the incoming data into multiple grouped output records

Question

I have three fields in the source, Student ID, Student name and Student Marks. I need to map the details in the destination, by grouping the data on the basis of marks obtained. Each time there's a new mark , the corresponding details of names and student
ID is saved under the a new mark group that is created. how do i come about it when there are n number of new marks?

Answer 1

for your scenario i used below xml as input,
<ns0:Students xmlns:ns0="http://BTSTempProj.StudentDetailsIn">
  <Student>
    <StudentID>StudentID_0</StudentID>
    <StudnetName>StudnetName_0</StudnetName>
    <StudentMarks>10</StudentMarks>
  </Student>
  <Student>
    <StudentID>StudentID_0</StudentID>
    <StudnetName>StudnetName_0</StudnetName>
    <StudentMarks>20</StudentMarks>
  </Student>
  <Student>
    <StudentID>StudentID_0</StudentID>
    <StudnetName>StudnetName_0</StudnetName>
    <StudentMarks>10</StudentMarks>
  </Student> 
  <Student>
    <StudentID>StudentID_0</StudentID>
    <StudnetName>StudnetName_0</StudnetName>
    <StudentMarks>10</StudentMarks>
  </Student>
  <Student>
    <StudentID>StudentID_0</StudentID>
    <StudnetName>StudnetName_0</StudnetName>
    <StudentMarks>20</StudentMarks>
  </Student>
  <Student>
    <StudentID>StudentID_0</StudentID>
    <StudnetName>StudnetName_0</StudnetName>
    <StudentMarks>30</StudentMarks>
  </Student>   
</ns0:Students>
and here is the output, hope this is what you are looking for. 
<ns0:Students xmlns:ns0="http://BTSTempProj.StudentDetailsOut">
<StudentMarks>10</StudentMarks>
<Student>
<StudentName>StudnetName_0</StudentName>
<StudentID>StudentID_0</StudentID>
<StudentName>StudnetName_0</StudentName>
<StudentID>StudentID_0</StudentID>
<StudentName>StudnetName_0</StudentName>
<StudentID>StudentID_0</StudentID>
</Student>
<StudentMarks>20</StudentMarks>
<Student>
<StudentName>StudnetName_0</StudentName>
<StudentID>StudentID_0</StudentID>
<StudentName>StudnetName_0</StudentName>
<StudentID>StudentID_0</StudentID>
</Student>
<StudentMarks>30</StudentMarks>
<Student>
<StudentName>StudnetName_0</StudentName>
<StudentID>StudentID_0</StudentID>
</Student>
</ns0:Students>
Please find the below xslt which you can use, it is basically based on the Muenchian grouping suggested by Ashwin
<?xml version="1.0" encoding="UTF-16"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:msxsl="urn:schemas-microsoft-com:xslt" xmlns:var="http://schemas.microsoft.com/BizTalk/2003/var" exclude-result-prefixes="msxsl var s0" version="1.0"
xmlns:ns0="http://BTSTempProj.StudentDetailsOut" xmlns:s0="http://BTSTempProj.StudentDetailsIn">
  <xsl:output omit-xml-declaration="yes" method="xml" version="1.0" />
  <xsl:template match="/">
    <xsl:apply-templates select="/s0:Students" />
  </xsl:template>
  <xsl:key name="groups" match="Student" use="StudentMarks"/>
  <xsl:template match="/s0:Students">
    <ns0:Students>
      <xsl:for-each select="Student[generate-id(.)=generate-id(key('groups',StudentMarks))]">
        <xsl:sort select="StudentMarks" order="ascending"/>
        <StudentMarks>
          <xsl:value-of select="StudentMarks/text()"/>
        </StudentMarks>    
        <Student>    
          <xsl:for-each select="key('groups',StudentMarks)">
            <StudentName>
              <xsl:value-of select="StudnetName/text()"/>
            </StudentName>
            <StudentID>
              <xsl:value-of select="StudentID/text()"/>
            </StudentID> 
            </xsl:for-each>
        </Student>
      </xsl:for-each>        
    </ns0:Students>
  </xsl:template>
</xsl:stylesheet>
Regards, Amit More