Sometimes you want to retrieve all tasks that are assigned to a user or to one of the SharePoint groups the user is a member of. This quite easy to accomplish through generation of a CAML query.

Just create an Or statement for tasks assigned to the user and loop through all of the groups in the SPUser object to add those to the query.

The resulting query will look like this:

<where>
	<or>
		<eq>
			<fieldRef Name='AssignedTo'/>
			<value Type='User'>Piet van Tul</value>
		</eq>
		<eq>
			<fieldRef Name='AssignedTo'/>
			<value Type='User'>Region Controllers</value>
		</eq>
	</or>
<where>

By using this query in the QueryOverride of a Content Query Web Part you have all the power of a Content Query combined with the power of query generation.