Re: Negative LIMIT and OFFSET?

From: Neil Conway <neilc(at)samurai(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Andrew Sullivan <ajs(at)crankycanuck(dot)ca>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Negative LIMIT and OFFSET?
Date: 2007-12-14 06:23:28
Message-ID: 1197613408.15124.9.camel@goldbach
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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.

-Neil

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