How is this possible?

I have two tables. 'services', and 'messages'. Each message can be
assigned to one service, or it can be unnasigned. Therefore 'service_id'
column in table 'messages' is not foreign-keyed to 'id' column in
services table. services.id is PK for services, messages.id is PK for
messages.

Now, here goes:

pulitzer2=# select * from services where id = 1001;
  id  | keyword | type_id | vpn_id | start_time |        end_time
| day_boundary | week_boundary | month_boundary | recurrence |
random_message_count
------+---------+---------+--------+------------+------------------------+--------------+---------------+----------------+------------+----------------------
 1001 | cocker  |       1 |      1 |            | 2005-10-20 12:00:00+02
|              |               |                |          1 |
(1 row)


Ok, I have a service with id 1001 which is called 'cocker'.

Now, I want all the messages for that service within certain period:

pulitzer2=# select * from messages where service_id = 1001 and
receiving_time between '2005-10-01' and '2005-10-30';
 id | from | to | receiving_time | raw_text | keyword | destination_id |
vpn_id | service_id | status | reply
----+------+----+----------------+----------+---------+----------------+--------+------------+--------+-------
(0 rows)

Ok, no such messages.


Now I want all services which didn't have any messages within certain
period:
pulitzer2=# select * from services where id not in (select distinct
service_id from messages where receiving_time between '2005-10-01' and
'2005-10-30');
 id | keyword | type_id | vpn_id | start_time | end_time | day_boundary
| week_boundary | month_boundary | recurrence | random_message_count
----+---------+---------+--------+------------+----------+--------------+---------------+----------------+------------+----------------------
(0 rows)

Why is that?



I 'discovered' above mentioned when I was transforming this query:

SELECT
        services.id AS service_id,
        (SELECT 
                COUNT(id)
        FROM
                messages
        WHERE
                (messages.service_id = services.id)
                AND (messages.receiving_time >= '2005-10-01')
                AND (messages.receiving_time < '2005-10-30')
        ) AS "count",
        services.keyword
FROM
        services
WHERE
        (services.vpn_id = 1)
        AND
        (
                (services.start_time IS NULL OR services.start_time <= 
'2005-10-30')
                AND
                (services.end_time IS NULL OR services.end_time >= '2005-10-01')
        )
GROUP BY
        services.id,
        services.keyword
ORDER BY
        services.keyword

[this query shows correctly, for service 'cocker', that '"count"' column
has value 0]


I transformed query to this:

SELECT
        services.id AS service_id,
        count(messages.id) as "count",
        services.keyword
FROM
        services
        LEFT OUTER JOIN messages
                ON services.id = messages.service_id
WHERE
        services.vpn_id = 1
        AND messages.receiving_time BETWEEN '2005-10-01' AND '2005-10-30'
GROUP BY
        services.id,
        services.keyword
ORDER BY
        services.keyword

This query runs MUCH faster, but it omits the 'cocker' column, as if I
used INNER JOIN. 

Any clues? I'm stuck here...

        Mike
-- 
Mario Splivalo
Mob-Art
[EMAIL PROTECTED]

"I can do it quick, I can do it cheap, I can do it well. Pick any two."



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