| From: | "David G(dot) Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com> |
|---|---|
| To: | jinhuilai(at)email(dot)ncu(dot)edu(dot)cn, PostgreSQL Bug List <pgsql-bugs(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: BUG #18932: PostgreSQL fails to handle EXCEPT operation when the left branch is an Empty Table |
| Date: | 2025-05-15 14:14:13 |
| Message-ID: | CAKFQuwb+7_eJSTJOcQ8pL37Dbt=i9FWQnvp+_SQHrBHeiWs2Cg@mail.gmail.com |
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| Lists: | pgsql-bugs |
On Thu, May 15, 2025, 07:25 PG Bug reporting form <noreply(at)postgresql(dot)org>
wrote:
> The following bug has been logged on the website:
>
> Bug reference: 18932
> Logged by: jinhui lai
> Email address: jinhuilai(at)email(dot)ncu(dot)edu(dot)cn
> PostgreSQL version: 17.5
> Operating system: ubuntu 22.04
> Description:
>
> Hi, PostgreSQL Developers,
> Please consider such query:
> SELECT * FROM empty_table EXCEPT SELECT * FROM not_empty_table;
> Obviously, the above query always returns an empty set. I think it should
> return an empty set quickly.
>
The failure to do so is not a bug. See other similar complaints in the
past month or so.
Patches in this area could be accepted but the corner cases being described
don't seem to be highly motivating.
David J.
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| Next Message | David G. Johnston | 2025-05-15 14:15:20 | Re: BUG #18930: PostgreSQL fails to handle INTERSECT operation involving Empty Table |
| Previous Message | PG Bug reporting form | 2025-05-15 13:42:30 | BUG #18933: PostgreSQL fails to handle JOIN operation involving Empty Table |