writing sql query
SELECT * from room
WHERE (roomNo, hotelNo) not in
( select roomNo, hotelNo
  from booking
  where datefrom between '2012-05-01' and '2012-11-01'
  or dateto between '2012-05-01' and '2012-11-01'
)

select r.* from rooms r
left outer join bookings b on b.roomno = r.roomno
where b.dateto not between '2012-05-01' and '2012-11-01'
and b.datefrom not between '2012-05-01' and '2012-11-01'
or b.roomno is null

SELECT * FROM Room r
JOIN Booking b ON b.hotelNo = r.hotelNo AND r.roomNo = b.roomNo
WHERE NOT ('2012-05-01' BETWEEN (b.dateFrom AND b.dateTo)
OR '2012-11-01' BETWEEN (b.dateFrom AND b.dateTo))