[MySQL 5] Fetching records for common dates

Hi peps,

I have a query about a hotel's room booking system.

Please take a look into the room table.



The following is the order table:






What query would fetch me the date(s) which has all rooms (8 in this case) booked on that date?

For this case it would be 2010-12-10 and 2010-12-20, since all 8 rooms have been booked for the date.






Please if anyone can help?

Many thanks in advance