BOOKING SYSTEM

Hi all I have a hotel booking system where for sppecific periods we have specific availability e.g. hotel_id, hotel_name, hotel_fromperiod, hotel_toperiod, hotel_availablesinglerooms 1, Hilton, 20/06/05, 20/08/05, 20 We have a second table for recording the bookings e.g.hotel1_id, hotel1_name, hotel1_fromperiod, hotel1_toperiod, hotel1_availablesinglerooms 1, Hilton, 01/07/05, 20/07/05, 1 2, Hilton, 20/06/05, 25/07/05, 1 3, Hilton, 25/06/05, 27/06/05, 19 4, Hilton, 05/07/05, 05/08/05, 2 Let's say that someone wants to book from the 25/06/05 - 29/06/05 what kind of function-SQL do I have to run to check whether there is availability? (in this example there should be availability between 27 and 29 but not between 25 and 27). Is this way of structuring the easiest and more efficient? Thank you Mario