Re: why at time zone tz_offset not equal tz_name? tz_name has same offset in pg_timezone_names

On Mon, Apr 28, 2025 at 7:40 PM H Witt <i5d(at)live(dot)com> wrote:

> select
> '2025-02-03 15:04:05'::*timestamptz* *at* *time* *zone* '+08:00',
> '2025-02-03 15:04:05'::*timestamptz* *at* *time* *zone* 'Asia/Shanghai'
>
> display
> |2025-02-02 23:04:05.000|2025-02-03 15:04:05.000|
>

When you write the former you get the POSIX convention for sign meaning (+
== West). When you write the latter you get the ISO convention (+ == East)

https://www.postgresql.org/docs/current/datetime-posix-timezone-specs.html

Since people expect ISO conventions you should stick to using the zone
names and forget explicit offsets (and even the abbreviations for good
measure) even exist.

David J.