XQuery booleans include:
AND
OR
NOT()
List books published by Addison-Wesley after 1993:
<bib>
{
FOR $b IN document("bib.xml")/bib/book
WHERE $b/publisher = "Addison-Wesley" AND $b/@year > 1993
RETURN
$b/title
}
</bib>
Adapted from XML Query Use Cases