hotel reservation system SQL: identify any room available in date range

Question

(In case this seems familiar: I asked a different question similar to this one, but I just got a note that the site design has changed and now the owners do want a

Answer 1

If I understood your db structure properly, you need to find a row in rooms with no corresponding rows in availability.

SELECT r.* 
FROM rooms r
  LEFT JOIN availability a ON (r.id = a.room_id 
 AND a.date_occupied BETWEEN :start_date AND :end_date)
WHERE a.id IS NULL