[kashperuk]

А если

while select PMPlaceSecurityTimetable
              exists join PlaceId from PMPlaceTimeBoard
                            where PMPlaceTimeBoard.DateStart == PMPlaceSecurityTimetable.DateSecure
        outer join PMPlaceTimeBoard1
              where PMPlaceTimeBoard1.DateStart == PMPlaceSecurityTimetable.DateSecure &&
                    PMPlaceTimeBoard1.PlaceId == PMPlaceSecurityTimetable.PlaceId
                {
                   if (PMPlaceTimeBoard1)
                       timeList2.ins(PMPlaceTimeBoard1);

                }

Код я не проверял - так просто, как идея.