grouped on All_parts.Part_ID
All_parts.fab can either be Y or N
I want both (all)  types of parts to show as a group

But in the details
If All_parts.fab = "Y" then only show data where Req.Type = "M"

(there are no details for All_parts.fab = "N" because these parts aren't on the 'Req' table )

How do I put this into a select expert?

(IF {all_parts_.FAB} = "Y" then {REQ.TYPE} = "M" )
doesn't include the parts where  {all_parts_.FAB} = "N"