Question

I have tables & data like this:

venues table contains : id

+----+---------+
| id | name    |
+----+---------+
|  1 | venue 1 |
|  2 | venue 2 |
---------------

event_dates : id, event_id, event_from_datetime, event_to_datetime, venue_id
+----+----------+---------------------+---------------------+----------+
| id | event_id | event_from_datetime | event_to_datetime   | venue_id |
+----+----------+---------------------+---------------------+----------+
|  1 |        1 | 2009-12-05 00:00:00 | 2009-12-07 00:00:00 |        1 |
|  2 |        1 | 2009-12-09 00:00:00 | 2009-12-12 00:00:00 |        1 |
|  3 |        1 | 2009-12-15 00:00:00 | 2009-12-20 00:00:00 |        2 |
+----+----------+---------------------+---------------------+----------+

This is my requirement: I want venues that will be free on 2009-12-06 00:00:00
i.e.

I should get

|venue_id|

|2 |

Currently I’m having the following query,

select ven.id , evtdt.event_from_datetime, evtdt.event_to_datetime 
from venues ven 
left join event_dates evtdt 
on (ven.id=evtdt.venue_id) 
where evtdt.venue_id is null 
or not ('2009-12-06 00:00:00' between evtdt.event_from_datetime 
                                  and evtdt.event_to_datetime);
+----+---------------------+---------------------+
| id | event_from_datetime | event_to_datetime   |
+----+---------------------+---------------------+
|  1 | 2009-12-09 00:00:00 | 2009-12-12 00:00:00 |
|  2 | 2009-12-15 00:00:00 | 2009-12-20 00:00:00 |
|  3 | NULL                | NULL                |
|  5 | NULL                | NULL                |
+----+---------------------+---------------------+

If you note the results, its not including venue id 1 where date is in between 2009-12-06 00:00:00 but showing other bookings.
Please help me correct this query.

Thanks in advance.

Answer 1

SELECT  *
FROM    venue v
WHERE   NOT EXISTS
        (
        SELECT  NULL
        FROM    event_dates ed
        WHERE   ed.venue_id = v.id
                AND '2009-12-06 00:00:00' BETWEEN ed.event_from_datetime AND ed.event_to_datetime
        )