From: | Manuel Sugawara <masm(at)fciencias(dot)unam(dot)mx> |
---|---|
To: | "Giorgio Andreoletti - mentelocale" <giorgio(dot)andreoletti(at)mentelocale(dot)it> |
Cc: | <pgsql-novice(at)postgresql(dot)org> |
Subject: | Re: problem selecting multiple records (again!) |
Date: | 2001-06-05 22:01:14 |
Message-ID: | m3g0de37th.fsf@dep1.fciencias.unam.mx |
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Thread: | |
Lists: | pgsql-novice |
something like
select * from events where ref in (select distinct ref from events limit 3);
will do what you want.
hth,
Manuel.
"Giorgio Andreoletti - mentelocale" <giorgio(dot)andreoletti(at)mentelocale(dot)it> writes:
> hi everyone,
> i already wrote to this list for the same problem.... i thought i had
> resolved it, but i was wrong !
> i'll explain my problem in a different (and simplier to understand) way:
>
> suppose you have a table representing some events like this:
>
> id | ref | date
> -----------------------
> 1 | 10 | 2001-05-10
> 2 | 10 | 2001-05-11
> 3 | 10 | 2001-05-12
> 4 | 20 | 2001-05-11
> 5 | 20 | 2001-05-13
> 6 | 30 | 2001-05-15
>
> the "ref" field is used to match this table with an another table containing
> the description of the event in that date.
> So, in this example I have the same event (identified as '10') which is
> repeated 3 times, another event ('20') repeated twice, and an event with a
> single occurance ('30').
> now suppose that today is 2001-05-09 and i want to publish on my web-site
> the next 3 events:
>
> doing a simple SELECT i will get :
>
> 1 | 10 | 2001-05-10
> 2 | 10 | 2001-05-11
> 4 | 20 | 2001-05-11
>
> but what i really wanted was :
>
> 1 | 10 | 2001-05-10
> 4 | 20 | 2001-05-11
> 6 | 30 | 2001-05-15
>
> i.e., i don't want to get more than one occurance of the same "ref".
>
> plz help me since i'm getting crazy trying to solve this problem !!!
> keep in mind that i'll have a table with hundreds of event, so the faster
> way to get the result is the preferred :-)
>
> the web publishing system is based on zope.
>
> tnx for your help
>
> ============================
> Giorgio Andreoletti - mentelocale S.r.l.
> responsabile hardware e networking
> responsabile sviluppo web
> www.mentelocale.it
> giorgio(dot)andreoletti(at)mentelocale(dot)it
> ============================
>
>
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