"select
top " + DropDownList5.SelectedValue + " roomno
from roomdetails
where
roomno not in
(
select roomno
from roombooking
where
(
(
'" + dt1 + "' between ArrivalDate and DepartureDate
)
)
and Category ='"+DropDownList2.SelectedValue+"'
)
and RoomCategory='"+DropDownList2.SelectedValue+"'"