>IIf(Trim(RQ.RQ_MOSJOB)<>"","Work Order",IIf(Trim(RQ.RQ_MOCNUMBER)<>"","Customer Order","Other")) AS [Reqt Type], 
>

case when len(Ltrim(RQ.RQ_MOSJOB)) > 0 
                   then "Work Order" 
                   else 
                        case when len(lTrim(RQ.RQ_MOCNUMBER)) > 0 
                                    then "Customer Order" 
                                    else "Other" END
                END as [Reqt Type]