Alexander Korotkov <a.korotkov@postgrespro.ru> writes: > On Mon, Jun 1, 2020 at 1:38 PM PG Bug reporting form > <noreply@postgresql.org> wrote: >> I execute a update SQL as below : >> update Table1 set date1=to_timestamp('19790701000000', 'YYYYMMDDHH24MISS') >> where ..... >> date1 is a timestamp type column, the result in DB is 1979-07-01 01:00:00 >> where come from that '01' hour ?
> It's likely related to clock shift in your timezone.
July 1 would be an odd time for a seasonal DST shift ... but quickly thumbing through the tzdata files, I see one for Asia/Taipei on that date in 1979. So I guess that the OP is using that zone, and the answer to the question is "midnight of that date did not exist in Taiwan; their clocks shifted forward from 23:59:59 to 01:00:00".