From: A. Kretschmer <andreas.kretschmer@schollglas.com>
To: pgsql-sql@postgresql.org
Subject: Re: list variable attributes in one select
Date: Mon, 22 Jan 2007 09:24:02 +0100
Message-ID: <20070122082402.GA27409@a-kretschmer.de> (raw)
In-Reply-To: <20070122074348.GA8177@apartia.fr>
References: <20070122074348.GA8177@apartia.fr>
am Mon, dem 22.01.2007, um 8:43:48 +0100 mailte Louis-David Mitterrand folgendes:
> "person_type" contains differents caracteristics for a person (actor,
> director, author, etc.) who can have several types, hence the need for
> the person_to_type table.
>
> I'd like to know if I can list in one SELECT command a person and all of
> its types, given that the number of types can be 0 to n.
>
> For example, for a given person I'd like to obtain:
>
> "John Doe", "actor", "playright", "author"
>
> or
>
> "Jane Doe", "director"
>
> in one select.
Yes,
imagine, you have 2 tables:
test=*# select * from f1;
id | name
----+------
1 | foo
2 | bar
3 | batz
(3 rows)
test=*# select * from f2;
i_id | f1_id
------+-------
1 | 1
1 | 2
2 | 1
2 | 2
2 | 3
(5 rows)
f1 contains your characteristics, f2 contains the assignment person ->
characteristics.
Now you can see all characteristics for person with id=1:
test=*# select array_to_string(array(select name from f1 where id in (select f1_id from f2 where i_id = 1)), ', ');
array_to_string
-----------------
bar, foo
(1 row)
Hope that helps, Andreas
--
Andreas Kretschmer
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To: pgsql-sql@postgresql.org
Cc: andreas.kretschmer@schollglas.com
Subject: Re: list variable attributes in one select
In-Reply-To: <20070122082402.GA27409@a-kretschmer.de>
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