From: D'Arcy J.M. Cain <darcy@druid.net>
To: Joel Richard <postgres@joelrichard.com>
Cc: Claudia Kosny <ckosny@gmx.net>
Cc: sql pgsql <pgsql-sql@postgresql.org>
Subject: Re: fetch first rows of grouped data
Date: Mon, 27 Aug 2007 14:15:52 -0400
Message-ID: <20070827141552.21ec3a54.darcy@druid.net> (raw)
In-Reply-To: <4CB5D209-C0CC-466E-A967-E766D6AD799B@joelrichard.com>
References: <46D2FD9F.3020000@gmx.net>
<20070827125102.e52b43de.darcy@druid.net>
<4CB5D209-C0CC-466E-A967-E766D6AD799B@joelrichard.com>
On Mon, 27 Aug 2007 13:34:09 -0400
Joel Richard <postgres@joelrichard.com> wrote:
> That's what I thought at first, but this is not the case. She's
> looking for the first two dates in -each- city in the table. I
> initially thought that this could be accomplished with GROUP BY and
> LIMIT, but GROUP BY can only give you the first date for each city,
> not the first two dates for each city.
Yes, you are correct. My mistake.
> So far, I haven't come up with any clever ideas. I'm not sure this
> can be done in SQL.
Well, I can think of an SQL only method involving a temporary table but
it would not be a single query:
- Select into temp table where date is max.
- Select from temp table union with main table where date is max and
is not in temp table.
--
D'Arcy J.M. Cain <darcy@druid.net> | Democracy is three wolves
http://www.druid.net/darcy/ | and a sheep voting on
+1 416 425 1212 (DoD#0082) (eNTP) | what's for dinner.
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To: pgsql-sql@postgresql.org
Cc: darcy@druid.net, postgres@joelrichard.com, ckosny@gmx.net
Subject: Re: fetch first rows of grouped data
In-Reply-To: <20070827141552.21ec3a54.darcy@druid.net>
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