My problem is I can't do a for-each on either the unit or the occupant;
if I do it on the unit, I'll only get one row for unit 1, and if I do it
on the occupant, I won't get any rows for 2. I also want to be have it
sorted by unit, so I wouldn't be able to do a for-each on all occupants,
then another on all units that don't have an occupant.

<xsl:stylesheet version="1.0"
     xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

<xsl:template match="root">
<xsl:for-each select="unit">
	<xsl:variable name="unit" select="."/>
	<xsl:variable name="occupants" select="key('occupant',id)"/>
	<xsl:choose>
		<xsl:when test="$occupants">
			<xsl:for-each select="$occupants">
				<xsl:value-of select="$unit/name"/> | <xsl:value-of select="name"/>
				<xsl:text>&#10;</xsl:text>
			</xsl:for-each>
		</xsl:when>
		<xsl:otherwise>
			<xsl:value-of select="$unit/name"/> | Vacant
		</xsl:otherwise>
	</xsl:choose>
</xsl:for-each>
</xsl:template>

regards,
--
Joris Gillis (http://users.telenet.be/root-jg/me.html)
B+Et ipsa scientia potestas estB;  - Francis Bacon , Meditationes sacrae