Re: Negative LIMIT and OFFSET? - Mailing list pgsql-hackers

From Simon Riggs
Subject Re: Negative LIMIT and OFFSET?
Date
Msg-id 1197643309.15521.116.camel@ebony.site
Whole thread Raw
In response to Re: Negative LIMIT and OFFSET?  (Neil Conway <neilc@samurai.com>)
Responses Re: Negative LIMIT and OFFSET?  (Simon Riggs <simon@2ndquadrant.com>)
Re: Negative LIMIT and OFFSET?  (Tom Lane <tgl@sss.pgh.pa.us>)
Re: Negative LIMIT and OFFSET?  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On Thu, 2007-12-13 at 22:23 -0800, Neil Conway wrote:
> On Thu, 2007-12-13 at 22:06 -0500, Tom Lane wrote:
> > I guess that on purely philosophical grounds, it's not an unreasonable
> > behavior.  For example, "LIMIT n" means "output at most n tuples",
> > not "output exactly n tuples".  So when it outputs no tuples in the face
> > of a negative limit, it's meeting its spec.
>
> If "LIMIT n" means "emit at most n tuples", then a query that produces 0
> rows with n < 0 is arguably violating its spec, since it has produced
> more tuples than the LIMIT specified (0 > n). Interpreted this way, no
> result set can be consistent with a negative limit, so I'd vote for
> throwing an error.

I even found an existing, unused error message called
ERRCODE_INVALID_LIMIT_VALUE

so here's a patch.

--
  Simon Riggs
  2ndQuadrant  http://www.2ndQuadrant.com

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