Question

EDIT: The query Gordon posted appears to have a problem. If I have a booking from 10-12 it seems to consider all bookings past 12 pm invalid, but all bookings before 10am valid.

Some quick and simple thinking ended up in me creating the following query:

SELECT serverip 
        FROM   server 
        WHERE  serverip NOT IN (SELECT serverip 
                                FROM   booking 
                                WHERE  startat >= datehere 
                                AND expiresat <= datehere) 
        LIMIT  1; 

Suppose the booking table stores the following:

+-----------+-----------+----------+----------+-----------+
| bookingid | serverip  | username | startat  | expiresat |
+-----------+-----------+----------+----------+-----------+
|         1 | 127.0.0.1 | testuser | 10:00    | 12:00     |
+-----------+-----------+----------+----------+-----------+

If the user was to input the following data for a booking:

startat = 9:59
expiresat = 12:01

They could easily bypass my check to see if the booking time is available based on previous bookings stored.

Any advice on how I could better solve this problem?

I would prefer NOT to limit the users input and would like to avoid hard coding specific time slots, if that wasn’t a problem however I would stick with what I’ve got.

Thanks for your time.

Answer 1

SELECT *
FROM server
WHERE serverip NOT IN
(SELECT serverip 
 FROM booking
 WHERE
   (startat <= '2013-01-30 08:00:00' AND expiresat >= '2013-01-30 08:00:00') OR
   (startat <= '2013-01-30 09:00:00' AND expiresat >= '2013-01-30 09:00:00') OR
   (startat >= '2013-01-30 08:00:00' AND expiresat <= '2013-01-30 09:00:00'))

Where 8:00 is start time and 9:00 is expire.