SOS! a tough XML extract issue.

Question

i have a xmltype table like this:
SQL> select object_value from tbl_testxml;
<members>
<grandfather name="Tom" age="66">
<father name="John" age="46">
<son name="Simon" age="20"/>
<son name="Steve" age="19"/>
</father>
<father name="Jeff" age="45">
<son name="Mark" age="17"/>
<son name="Mathiew" age="15"/>
</father>
</grandfather>
</members>
What i want to do is extract the grandfather, father and son's name (in the same line if they are in same family), so i use this sql query:
select extract(value(v_xml),'//grandfather/@name') as grandfather,
extract(value(v_xml),'//grandfather/father/@name') as father,
extract(value(v_xml),'//grandfather/father/son/@name') as son
from tbl_testxml t,
TABLE (XMLSEQUENCE (EXTRACT (t.object_value, '/members'))) v_xml;
The output is like this eventually:
grandfather                              father                                  son
========                                 ==============                          ================
Tom                                       JohnJeff                               SimonSteveMarkMathiewBut this is not what i want, what i want is like this:
grandfather          father         son
========             ======         ======
Tom                   John           Simon
Tom                   John           Steve
Tom                   Jeff            Mark
Tom                   Jeff            Mathiewis that possible to get the result as above?
i've tried xmlquery, xmltable etc, none of them works :(
Thanks so much!
Edited by: user3318788 on Jul 10, 2009 5:14 PM
Edited by: user3318788 on Jul 11, 2009 5:23 PM
Edited by: user3318788 on Jul 11, 2009 5:29 PM

Answer 1

Certainly not the ideal solution, but you could transform the original XML using XSL so that it better fits your requirement :
SELECT extractvalue(v_xml.column_value,'//grandfather') as grandfather,
       extractvalue(v_xml.column_value,'//father') as father,
       extractvalue(v_xml.column_value,'//son') as son
FROM tbl_testxml t,
TABLE(
XMLSEQUENCE(
  EXTRACT(t.object_value.transform(
          xmltype('<?xml version="1.0"?>
          <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
          <xsl:template match="/">
          <all_branches>
           <xsl:for-each select="//son">
            <branch>
             <grandfather><xsl:value-of select="../../@name"/></grandfather>
             <father><xsl:value-of select="../@name"/></father>
             <son><xsl:value-of select="@name"/></son>
            </branch>
           </xsl:for-each>
          </all_branches>
          </xsl:template>
          </xsl:stylesheet>')
          ), '//branch'
) v_xml;Basically, the XSL takes each leaf (ie each son), retrieves its ancestors and presents them all in distinct BRANCH element.
The SQL query then just extracts all BRANCH nodes with XMLSEQUENCE (XMLTABLE works as well) and extracts again each member in separate column.