From: | Simon Riggs <simon(at)2ndquadrant(dot)com> |
---|---|
To: | Neil Conway <neilc(at)samurai(dot)com> |
Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Andrew Sullivan <ajs(at)crankycanuck(dot)ca>, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: Negative LIMIT and OFFSET? |
Date: | 2007-12-14 14:41:49 |
Message-ID: | 1197643309.15521.116.camel@ebony.site |
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Lists: | 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
Attachment | Content-Type | Size |
---|---|---|
error_if_negative.v1.patch | text/x-patch | 1.5 KB |
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