Find the number of rooms availble from the below table structure - php

Question

I have the following table structure:
roominfo table
+---------+----------------+---------------+
| Room_id | room_type_name | maximum_rooms |
+---------+----------------+---------------+
| 1 | A | 16 |
| 2 | B | 14 |
| 3 | C | 7 |
| 4 | D | 2 |
| 5 | E | 2 |
+---------+----------------+---------------+
bookedtable stores all the rooms booked within that date:
+------------+--------------+---------------+----------------+---------+
| room_bk_id | checkin_date | checkout_date | maxroomsbooked | room_id |
+------------+--------------+---------------+----------------+---------+
| 1 | 2014-01-28 | 2014-01-29 | 8 | 1 |
| 2 | 2014-01-29 | 2014-01-30 | 2 | 4 |
| 3 | 2014-01-28 | 2014-01-29 | 4 | 1 |
+------------+--------------+---------------+----------------+---------+
bookingprogress table to avoid the race condition (it blocks upto the expire time) I set the maximum expire time as 15 minutes from current time
+------------+----------------+-----------------+----------------+---------+---------------+---------------------+
| room_pg_id | checkinpg_date | checkoutpg_date | maxroomsbooked | room_id | sessionid | ExpireTime |
+------------+----------------+-----------------+----------------+---------+---------------+---------------------+
| 1 | 2014-01-28 | 2014-01-29 | 2 | 1 | AdsddsA23asd | 2014-01-28 00:15:00 |
| 2 | 2014-01-29 | 2014-01-30 | 2 | 5 | AdsQWerasdwe | 2014-01-28 00:18:00 |
| 3 | 2014-01-28 | 2014-01-29 | 1 | 2 | BdrtQWerasdwe | 2014-01-28 00:20:00 |
+------------+----------------+-----------------+----------------+---------+---------------+---------------------+
The workflow is:
User checks for the available rooms by providing checkin date, checkout date and no of rooms.
I need to find and display the rooms are available which are not blocked or booked for that particular period.
The executed query was (might be small mistakes -- Here I gave overview of what I have done --So modified my query according to that)
SELECT tbook.*,
SUM(tbook.maxroomsbooked + tprogress.maxroomsbooked) AS bookedrooms
FROM bookedtable AS tbook
JOIN bookingprogress AS tprogress USING (Room_id)
JOIN roominfo AS troomtype USING (Room_id)
WHERE tbook.checkout_date > '2014-01-28'
AND tprogress.checkoutpg_date > '2014-01-28'
AND tprogress.ExpireTime < '2014-01-27 00:10:00'
AND tprogress.room_id = 1
GROUP BY Room_id
From the above tables I tried to get the rooms which are available for booking. But I didn't get the expected result.
See it on sqlfiddle.
Could you please provide me with the solution?

Answer 1

One way would be to use NOT EXISTS subqueries. For example, if a user is interested in booking '2014-02-01' to '2014-02-07':
SELECT *
FROM roominfo r
WHERE NOT EXISTS (
SELECT *
FROM bookedtable b
WHERE b.room_id = r.room_id
AND NOT (
b.checkin_date < '2014-02-07'
AND b.checkout_date > '2014-02-01'
)
LIMIT 1
)
AND NOT EXISTS (
SELECT *
FROM bookingprogress p
WHERE p.room_id = r.room_id
AND p.ExpireTime > CURRENT_TIME
AND NOT (
p.checkinpg_date < '2014-02-07'
AND p.checkoutpg_date > '2014-02-01'
)
LIMIT 1
)