Muenchian grouping difficulties - sharepoint

Question

I am building a Sharepoint search results page to find the answers to questions asked in a 3rd party tool.
I have a bdc connection to their sql db.
I am crawling just one one table in the db.
I need to group question and answer results together using the muenchian method using several columns in the same table.
I cant change the db so I have to pull the results together in search to be something meaningful.
This table contains all the entries of questions asked and answers given.
I have to tie them together for us using search as the application to present the Q&A
overview of the data:
Each record returned in the core search results has an:
title - this is the question or the answer
activityid(int) - unique id of the entry
activitytypeid(int) - these identify if its a Q or A / 79 or 82
parentid(int) - this value contains the activityid of the original question - if the record is the original question, it will have a value of 0 for this column
isanswer(boolean) true or nothing (this is sort of redundant and does the same as activitytypeid but I was not sure if I could use it to help with the grouping)
Review
activitype id is either:
79 - question being asked - this will have a parentid of 0
or
82 - answer to question - this will have a parent id matching the activityid of the original question
I am trying but without much success to get my search results grouped/sorted to have the question returned first. In the example below it would be activityid 19142 and the answers to the question indented underneath with all grouped in a set
any help in reviewing my hack at this or examples would be great.
I am just trying to understand xsl and this has been a big learning curve. I have a long way to go and most certainly have jumped into the deep end on this.
raw xml of results i currently get without formatting the results
<All_Results>
<Result>
<id>1</id>
<title>Original Question</title>
<isanswer></isanswer>
<parentid>0</parentid>
<activitytype>79</activitytype>
<activityid>19142</activityid>
</Result>
<Result>
<id>2</id>
<title>Answer to original question</title>
<isanswer>true</isanswer>
<parentid>19142</parentid>
<activitytype>82</activitytype>
<activityid>19146</activityid>
</Result>
<Result>
<id>3</id>
<title>Another Question</title>
<isanswer></isanswer>
<parentid>0</parentid>
<activitytype>79</activitytype>
<activityid>19200</activityid>
<Result>
<Result>
<id>4</id>
<title>Second answer to original question</title>
<isanswer>true</isanswer>
<parentid>19142</parentid>
<activitytype>82</activitytype>
<activityid>19199</activityid>
</Result>
<Result>
<id>5</id>
<title>and another Question</title>
<isanswer></isanswer>
<parentid>0</parentid>
<activitytype>79</activitytype>
<activityid>19254</activityid>
<Result>
<Result>
<id>6</id>
<title>Answer to another question</title>
<isanswer>true</isanswer>
<parentid>19200</parentid>
<activitytype>82</activitytype>
<activityid>19265</activityid>
</Result>
</All_Results>
The output I am looking for would have all answers grouped with the corresponding question this is very simplified but I think it get s the point I am trying to get too.
<All_Results>
<Result>
<title>Original Question</title>
<title>Answer to original question</title>
<title>Second answer to original question</title>
</Result>
<Result>
<title>Another Question</title>
<title>Answer to another question</title>
</Result>
</All_Results>
my attempts at the template
<xsl:template match="All_Results">
<xsl:for-each select="Result[count(. | key('QAsked', 'activityid')[1]) > 0]">
<xsl:sort select="questionasked" />
<xsl:value-of select="title" /><br />
<xsl:value-of select="questionasked" /><br />
<xsl:value-of select="activityid" /><br /><br />
<xsl:for-each select="key('QAsked', '82')">
<xsl:sort select="questionasked" />
<xsl:if test="normalize-space(questionasked) = '82'"></xsl:if><br />
<xsl:value-of select="questionasked" /><br />
<xsl:value-of select="originalquestion" /><br />
<xsl:value-of select="likes" /><br /><br />
</xsl:for-each>
</xsl:for-each>
</xsl:template>

Answer 1

Try this template:
<xsl:key name="QAsked" match="Result[(activitytype = '82') or (activitytype = '79')]" use="concat(substring(parentid, 1, number(not(parentid = '0')) * string-length(parentid)),substring(activityid, 1, number(parentid = '0') * string-length(activityid)))"/>
<xsl:template match="All_Results">
<All_Results>
<xsl:for-each select="Result[count(. | key('QAsked', concat(substring(parentid, 1, number(not(parentid = '0')) * string-length(parentid)),substring(activityid, 1, number(parentid = '0') * string-length(activityid))))[1]) = 1]">
<xsl:sort select="id" />
<Result>
<xsl:for-each select="key('QAsked', concat(substring(parentid, 1, number(not(parentid = '0')) * string-length(parentid)),substring(activityid, 1, number(parentid = '0') * string-length(activityid))))">
<xsl:sort select="parentid" />
<title>
<xsl:value-of select="title" />
</title>
</xsl:for-each>
</Result>
</xsl:for-each>
</All_Results>
</xsl:template>
The output is xml structure which you provided as an example of the desired result.