مساعده في طريقة بحث

قد يقيد هذا الكود

declare @dRegStartDate datetime
declare  @dRegEndDate datetime

select *
from Rooms
left join
	(
		SELECT nRoomCode 
		FROM Rooms 
		WHERE 
					(
							dStartDate>=@dRegStartDate 
						And 
							dStartDate<=@dRegEndDate
					) 		
				OR 
					(
							dEndDate>=@dRegStartDate 
						And 		
							dEndDate<=@dRegEndDate
					) 
				OR
					(
							dStartDate<=@dRegStartDate
						AND 
							dEndDate>=@dRegEndDate
					)  
	) as UseRooms
Rooms.nRoomCode=useRooms.nRoomCode
where
		useRooms.nRoomCode is null

بالتوفيق