From: | Robert Treat <xzilla(at)users(dot)sourceforge(dot)net> |
---|---|
To: | pgsql-general(at)postgresql(dot)org |
Cc: | "chris smith" <dmagick(at)gmail(dot)com>, Andrus <eetasoft(at)online(dot)ee> |
Subject: | Re: How to use result column names in having cause |
Date: | 2006-03-31 14:46:14 |
Message-ID: | 200603310946.14941.xzilla@users.sourceforge.net |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-general |
On Friday 31 March 2006 08:30, chris smith wrote:
> On 3/31/06, Andrus <eetasoft(at)online(dot)ee> wrote:
> > >> In real application I have long expression instead of 123 and do'nt
> > >> want repeat this expression in HAVING clause.
> > >
> > > You have to repeat the expression. "AS" changes the output name, it
> > > can't be used either in the where clause or any other limiting factor
> > > like 'having':
> >
> > Doc about HAVING condition says:
> >
> > Each column referenced in condition must unambiguously reference a
> > grouping colum
> >
> > HAVING x> AVG(bar) unambiguously references to a grouping column x
> >
> > Is this bug ? It is very tedious to repeat same column expression in a
> > multiple times: one time in column expression, and n times in having
> > clause.
>
> But you're not referencing x, you're trying to use AVG(bar) in your
> expression.
>
>
> I assume it's this way because the standard says so.. one of the more
> knowledgable list members will be able to confirm/deny this.
>
Yes, this behavior is driven by the sql standards. There is actually a very
nice paper on this subject if you are interested
http://web.onetel.com/~hughdarwen/TheThirdManifesto/Importance-of-Column-Names.pdf
--
Robert Treat
Build A Brighter Lamp :: Linux Apache {middleware} PostgreSQL
From | Date | Subject | |
---|---|---|---|
Next Message | Tom Lane | 2006-03-31 15:03:57 | Re: configure: error: file 'tclConfig.sh' is required for Tcl |
Previous Message | Tony Caduto | 2006-03-31 14:43:28 | Re: pgsql continuing network issues |