New to PHP & mySQL

Hi all (details of database at then end of this message) I hope someone can give me some advice. I am trying to create a database and access via PHP for a friend of mine that has a caravan park. What I want him to be able to do is to add bookings for the caravans via a PHP page and for clients to be able to search to see if a caravan is available for rent. I have created 2 tables and have put data into it via command prompt and also retrieved the data from it and carried out a join linking the 2 tables together. Which all seems to work well. The one thing I cannot get into my head is how can you tell the database that all the days between the "start" and "end" dates are booked. Also when people search for a caravan on a specific date and say they want it for 7 day the database/PHP checks to see if the entire period is totally free for them and does not colide with another booking. I am not sure whether I should be in list list of the PHP list so sorry if I have got it wrong. Any advice or places to visit would be greatly appreciated. Thanks for all your help Ray Details of what i have done already: mysql> use matrix Database changed mysql>CREATE TABLE bookings ( -> booking_id SMALLINT (6) NOT NULL AUTO_INCREMENT, -> booking_start DATE NOT NULL DEFAULT '0000-00-00', -> booking_end DATE NOT NULL DEFAULT '0000-00-00', -> villa_id SMALLINT (6) NOT NULL DEFAULT '0', -> PRIMARY KEY (booking_id) -> ); mysql>INSERT INTO bookings VALUES (1, '2002-04-01', '2002-04-15', 3); mysql>INSERT INTO bookings VALUES (2, '2002-03-23', '2002-04-04', 1); mysql>CREATE TABLE villas ( -> villa_id SMALLINT (6) NOT NULL AUTO_INCREMENT, -> vill_name VARCHAR (25) NOT NULL DEFAULT '', -> PRIMARY KEY (villa_id) -> ); mysql>INSERT INTO villas VALUES (1, 'Gandy'); mysql>INSERT INTO villas VALUES (2, 'Hathaway'); mysql>INSERT INTO villas VALUES (3, 'Healy'); mysql>INSERT INTO villas VALUES (4, 'Mcleod'); mysql> SELECT * FROM bookings; +------------+---------------+-------------+-----------------+ | booking_id | booking_start | booking_end | villa_id | +------------+---------------+-------------+-----------------+ | 1 | 2002-04-01 | 2002-04-15 | 3 | | 2 | 2002-03-23 | 2002-04-04 | 1 | +------------+---------------+-------------+-----------------+ 2 rows in set (0.17 sec) mysql> SELECT * FROM villas; +----------+------------+ | villa_id | villa_name | +----------+------------+ | 1 | Gandy | | 2 | Hathaway | | 3 | Healy | | 4 | Mcleod | +----------+------------+ 4 rows in set (0.00 sec) mysql> SELECT villa_name, booking_start, booking_end FROM bookings LEFT JOIN villas ON bookings.villa_id = villas.villa_id; +------------+---------------+--------------------+ | villa_name | booking_start | booking_end | +------------+---------------+--------------------+ | Healy | 2002-04-01 | 2002-04-15 | | Gandy | 2002-03-23 | 2002-04-04 | +------------+---------------+--------------------+ 2 rows in set (0.00 sec)