separate XML results into 2+ groups using XSL - xslt

Question

I'm having trouble creating the XSLT to do something that I think should be straightforward...
Given the following XML:
<DATA_DS>
<LIST_ITEMS>
<ITEMS>
<abc>2011</abc>
<def>ABC Company</def>
<value>23</value>
</ITEMS>
<ITEMS>
<abc>2011</abc>
<def>ABC Company 1</def>
<value>11</value>
</ITEMS>
<ITEMS>
<abc>2010</abc>
<def>ABC Company 2</def>
<value>15</value>
</ITEMS>
<ITEMS>
<abc>2010</abc>
<def>ABC Company 3</def>
<value>6</value>
</ITEMS>
<ITEMS>
<abc>2010</abc>
<def>ABC Company 4</def>
<value>44</value>
</ITEMS>
</LIST_ITEMS></DATA_DS>
how would I go about transforming it using XSLT into something like this:
<table>
<row>23</row>
<row>11</row>
</table>
<table>
<row>15</row>
<row>6</row>
<row>44</row>
</table>
the idea is to create a new "table" every time a new "abc" is encountered

Answer 1

In xslt 2.0 instruction for-each-group is what you are looking for.
Following stylesheet
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:fo="http://www.w3.org/1999/XSL/Format" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:fn="http://www.w3.org/2005/xpath-functions">
<xsl:output method="xml" encoding="UTF-8" indent="yes" />
<xsl:template match="/">
<output>
<xsl:for-each-group select="DATA_DS/LIST_ITEMS/ITEMS" group-by="abc">
<table>
<xsl:for-each select="current-group()">
<row>
<xsl:value-of select="current()/value" />
</row>
</xsl:for-each>
</table>
</xsl:for-each-group>
</output>
</xsl:template>
</xsl:stylesheet>
produces output
<?xml version="1.0" encoding="UTF-8"?>
<output>
<table>
<row>23</row>
<row>11</row>
</table>
<table>
<row>15</row>
<row>6</row>
<row>44</row>
</table>
</output>