XSLT 1.0 transformation - xslt

Question

I'm trying to transform a XML file with XSLT 1.0 but I'm having troubles with this.
Input:
<task_order>
<Q>
<record id="1">
<column name="task_externalId">SPLIT4_0</column>
</record>
<record id="2">
<column name="task_externalId">SPLIT4_1</column>
</record>
</Q>
<task>
<id>SPLIT4</id>
<name>test</name>
</task>
</task_order>
Wanted result:
For each task_order element: When there is more than 1 record-element (SPLIT4 and SPLIT4_1) I need to duplicate the task element and change the orginal task-id with the id from record elements.
<task_order>
<Q>
<record id="1">
<column name="task_externalId">SPLIT4_0</column>
</record>
<record id="2">
<column name="task_externalId">SPLIT4_1</column>
</record>
</Q>
<task>
<id>SPLIT4_0</id>
<name>test</name>
</task>
<task>
<id>SPLIT4_1</id>
<name>test</name>
</task>
</task_order>
Any suggestions?
Thank you

Answer 1

First start off with the Identity Template which will handle copying across all existing nodes
<xsl:template match="#*|node()">
<xsl:copy>
<xsl:apply-templates select="#*|node()"/>
</xsl:copy>
</xsl:template>
Next, to make looking up the columns slightly easier, consider using an xsl:key
<xsl:key name="column" match="column" use="substring-before(., '_')" />
Then, you have a template matching task where you can look up all matching column elements using the key, and create a new task element for each
<xsl:template match="task">
<xsl:variable name="task" select="." />
<xsl:for-each select="key('column', id)">
<!-- Create new task -->
</xsl:for-each>
</xsl:template>
Try this XSTL
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
<xsl:output method="xml" indent="yes" />
<xsl:key name="column" match="column" use="substring-before(., '_')" />
<xsl:template match="task">
<xsl:variable name="task" select="." />
<xsl:for-each select="key('column', id)">
<task>
<id><xsl:value-of select="." /></id>
<xsl:apply-templates select="$task/*[not(self::id)]" />
</task>
</xsl:for-each>
</xsl:template>
<xsl:template match="#*|node()">
<xsl:copy>
<xsl:apply-templates select="#*|node()"/>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>