declare @per xml;
set @per = '<Persons>
<Person id="1">
<Name>
<FirstName>Bob</FirstName>
<LastName>Smith</LastName>
</Name>
<Age>52</Age>
</Person>
<Person id="2">
<Name>
<FirstName>Niels</FirstName>
<LastName>Jones</LastName>
</Name>
<Age>28</Age>
</Person>
<Person id="3">
<Name>
<FirstName>Brian</FirstName>
<LastName>Gates</LastName>
</Name>
<Age>30</Age>
</Person>
</Persons>';
select @per.query('for $p in /Persons/Person where $p/Age > 29 return $p/Name');

select @per.query('for $p in /Persons/Person
where $p/Age > 29
return $p/Name/FirstName');

<FirstName>Bob</FirstName>
<FirstName>Brian</FirstName>