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* LEFT JOIN on one and/or another column
@ 2004-01-29 04:27 Octavio Alvarez <alvarezp@alvarezp.ods.org>
2004-01-29 13:00 ` Re: LEFT JOIN on one and/or another column Bruno Wolff III <bruno@wolff.to>
0 siblings, 1 reply; 2+ messages in thread
From: Octavio Alvarez @ 2004-01-29 04:27 UTC (permalink / raw)
To: pgsql-sql
Hi. I have a table with two foreign keys (1 field each), like in
id | serial
ext_key_original | integer
ext_key_exception | integer
They mean different things, as one refers to a typical value, and the
other one refers to an exception that applies for that tuple.
Each key references a different table, one with typical data, and one with
exception data.
I'd like to join on the original, except when exception <> NULL, but I
can't quite figure out how to do so.
Can anyone help?
Thanks you. :-)
Octavio.
--
Octavio Alvarez.
E-mail: alvarezp@alvarezp.ods.org.
Agradezco que sus correos sean enviados siempre a esta dirección.
^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: LEFT JOIN on one and/or another column
2004-01-29 04:27 LEFT JOIN on one and/or another column Octavio Alvarez <alvarezp@alvarezp.ods.org>
@ 2004-01-29 13:00 ` Bruno Wolff III <bruno@wolff.to>
0 siblings, 0 replies; 2+ messages in thread
From: Bruno Wolff III @ 2004-01-29 13:00 UTC (permalink / raw)
To: Octavio Alvarez <alvarezp@alvarezp.ods.org>; +Cc: pgsql-sql
On Wed, Jan 28, 2004 at 20:27:00 -0800,
Octavio Alvarez <alvarezp@alvarezp.ods.org> wrote:
>
> Hi. I have a table with two foreign keys (1 field each), like in
>
> id | serial
> ext_key_original | integer
> ext_key_exception | integer
>
> They mean different things, as one refers to a typical value, and the
> other one refers to an exception that applies for that tuple.
>
> Each key references a different table, one with typical data, and one with
> exception data.
>
> I'd like to join on the original, except when exception <> NULL, but I
> can't quite figure out how to do so.
I am not completely sure from your description what exactly you are trying
to do, but it sounds like you can left join your table to the two foreign
key tables and then use coallesce to grab the value from the appropiate
joined table.
^ permalink raw reply [nested|flat] 2+ messages in thread
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2004-01-29 04:27 LEFT JOIN on one and/or another column Octavio Alvarez <alvarezp@alvarezp.ods.org>
2004-01-29 13:00 ` Bruno Wolff III <bruno@wolff.to>
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