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Re: Problem with ORDER BY and DISTINCT ON

From: Steve Midgley <public(at)misuse(dot)org>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-sql(at)postgresql(dot)org
Subject: Re: Problem with ORDER BY and DISTINCT ON
Date: 2008-08-01 03:35:15
Message-ID: 20080801054552.47D8564FD23@postgresql.org (view raw or flat)
Thread:
Lists: pgsql-sql
At 03:51 PM 7/31/2008, Tom Lane wrote:
>Steve Midgley <public(at)misuse(dot)org> writes:
> > At 07:29 AM 7/16/2008, Tom Lane wrote:
> >> I think what is happening is that ORDER BY knows that and gets rid 
> of
> >> the duplicate entries while DISTINCT ON fails to do so.
>
> > Of course removing the duplicate from both areas is the correct
> > solution and I broke down and hacked that into the auto-sql-writing 
>
> > code and so my immediate problem is solved. I'm happy to file this 
> as a
> > ticket for Pg (please point me to your ticket tool as I've never 
> used
> > it). This is not a very big deal but Pg has such a high compliance 
> with
> > wacky-but-valid SQL it does seem like it should be fixed just 
> because.
>
>I've applied a patch for this to CVS HEAD.  I doubt we'll try to fix 
>it
>in the back branches, though --- it's too much of a corner case to be
>worth taking any risk of breaking other stuff.
>
>                         regards, tom lane
Hey Tom,

That's really great - thanks. I'm impressed how quickly you are fixing 
this obscure issue. I came from MS SQL and it would be hard for me to 
put into words how much of a better job you all are doing on Pg.

Best,

Steve


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