Re: Query combination query.

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От Sean Davis
Тема Re: Query combination query.
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Msg-id 3FAE5C17-84C3-11D9-A6C7-000D933565E8@mail.nih.gov
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Ответ на Query combination query.  (john-paul delaney <jp@justatest.com>)
Ответы Re: Query combination query.  (john-paul delaney <jp@justatest.com>)
Perl DBI connection to Postgres  (SG Edwards <s0460205@sms.ed.ac.uk>)
Список pgsql-novice
Untested, but how about something like:

SELECT subject,created,topic_id,(select count(topic_seq) from
ap_form_msq as b where b.topic_id=a.topic_id) from ap_forum_msq as a
where topic_seq=1;

Sean

On Feb 22, 2005, at 6:20 AM, john-paul delaney wrote:

> Hello List... Newbie question - is it possible to combine the following
> two queries into one query statement returning, subject, created,
> topic_id, count?
>
> thanks,
> /j-p.
>
>
> (Query1)
>  SELECT subject, created, topic_id FROM ap_forum_msg WHERE topic_seq =
> 1;
>
>      subject     |            created            | topic_id
> -----------------+-------------------------------+----------
>  A topic test 00 | 2005-02-22 09:14:25.444209+01 |        1
>  A topic test 01 | 2005-02-22 09:15:44.320408+01 |        2
>
>
>
> (Query 2)
>  SELECT topic_id, count(topic_seq) FROM ap_forum_msg GROUP BY topic_id;
>
>  topic_id | count
> ----------+-------
>         1 |     2
>     2 |     3
>
>
> (Table ap_forum_msg)
>
>   Column   |           Type           |   Modifiers
>  ----------+--------------------------+---------------
>  topic_id  | integer                  | not null
>  topic_seq | integer                  | not null
>  author_id | integer                  | not null
>  created   | timestamp with time zone | default now()
>  subject   | character varying(100)   |
>  msg_text  | character varying        |
>  forum_id  | integer                  | not null
>  Indexes: ap_forum_msg_pkey primary key btree (topic_id,
>  topic_seq)
>  Foreign Key constraints: $1 FOREIGN KEY (author_id) REFERENCES
>  apo_artist(apo_art_id) ON UPDATE NO ACTION ON DELETE NO ACTION,
>       $2 FOREIGN KEY (forum_id) REFERENCES
>       ap_forum(forum_id) ON UPDATE NO ACTION ON DELETE CASCADE
>
>
> --
>
>
> ---------------------------(end of
> broadcast)---------------------------
> TIP 9: the planner will ignore your desire to choose an index scan if
> your
>       joining column's datatypes do not match


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