Customer(ID, name, birthDate, city);
Room(number, floor, beds, roomtype, price);
Bookings(Customer, roomNumber, floor, checkInDate, checkOutDate);

select Customer from Bookings
   join Room on(Bookings.num = camera.roomNumber and Bookings.floor=
   Room.floor)
        where (Bookings.Customer, Bookings.floor) not in (select number, floor from
        Room where roomType != 'economic')