Does Query Builder have an option that works like a CASE statement?

I am new to Windchill.  I have some experiencing in creating reports using other software.  What I want to do is create a report that shows the current incomplete task and assignee associated with an open change request.  If a change notice is associated with a change request, I want to  display the current incomplete task and assignee associated with the the change notice.  As I understand it, when I retrieve the tasks associated with the CR, I'm only retrieving the tasks within the CR's workflow.  In order to also retrieve the CN task, I would need to have the query check the state of the CR and if it is approved, retrieve the task associated with the change notice's workflow.   In my past experience, I would have used a CASE statement  to provide the IF - THEN- ELSE functionality but I'm stumped on how to do that within query builder.  Has anyone done something similar?  I've read every resource document I can find but I have yet to come across anything that seems to address this type of situation.