Re: Question on cast string to date

On Monday, May 9, 2022, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> =?UTF-8?B?5q2j5Y2O5ZCV?= <kainwen(at)gmail(dot)com> writes:
> > I test the following SQL in pg15dev (seems same behavior as the
> > previous version).
> > select '2020701'::date;
> > date
> > ------------
> > 0202-07-01
> > (1 row)
> > At the first glance, the result seems quite strange.
>
> [ shrug... ] You left out a zero. It's not apparent to me that
> this answer is wrong.

> If you want to pursue this question, you could start by bisecting
> to find just which commit changed it and why.
>
>
Manual history inspection of datetime.c

https://github.com/postgres/postgres/commit/7778ddc7a2d5b006edbfa69cdb44b8d8c24ec1ff

https://www.postgresql.org/message-id/flat/8977CB36860C5843884E0A18D8747B0372BC6401%40szxeml558-mbs.china.huawei.com#8aa7c8b8916056a53f6c6dff0f0eb428

The goal seemed to be able to accept 5-digit years…this behavior change
didn’t show in the tests (or discussion) though I didn’t look for the of
testing the pre-existing failure mode.

David J.