From: Greg Stark <gsstark@mit.edu>
To: Christoph Haller <ch@rodos.fzk.de>
Cc: pgsql-sql@postgresql.org
Cc: cprice@hrdenterprises.com
Subject: Re: LIMIT and SUBQUERIES
Date: 05 Mar 2003 10:22:46 -0500
Message-ID: <87fzq196t5.fsf@stark.dyndns.tv> (raw)
In-Reply-To: <3E65FA8B.352136E@rodos.fzk.de>
References: <3E65FA8B.352136E@rodos.fzk.de>
Christoph Haller <ch@rodos.fzk.de> writes:
> >
> > So anyway, I have the query that is working - but it returns all
> > records for all owners, when what I really want to do is return the
> > top 5 per each owner.
> >
> I've seen a lot of questions like this on the list before about
> filtering
> result sets. Within the most replies, people were told to use middleware
>
> stuff like perl, awk, sed, ... to filter out unwanted rows, because SQL
> was not intended to do so.
This is the same problem as the "ranking" problem that I mentioned earlier.
http://archives.postgresql.org/pgsql-sql/2003-03/msg00013.php
Essentially we would need a kind of feature that has some similarities to user
defined aggregates but is not exactly the same thing. The feature doesn't
currently exist, and I haven't seen it in order databases, so I don't even
know exactly what it would look like.
--
greg
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To: pgsql-sql@postgresql.org
Cc: gsstark@mit.edu, ch@rodos.fzk.de, cprice@hrdenterprises.com
Subject: Re: LIMIT and SUBQUERIES
In-Reply-To: <87fzq196t5.fsf@stark.dyndns.tv>
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