Re: Sybase to postgres Timestamp column

A couple of things to look out for in terms of dates that I have come across.  First, date formats:
Aug 20 2004  4:23:07.786PM -- Postgres
Aug 20 2004  4:23:07:786PM -- Sybase
Note the separator difference between seconds and milliseconds (dot vs. colon).
Second: date math is different for Sybase vs. Postgres.  A difference in days in Sybase is computed by counting date thresholds crossed.  If I recall, Postgres counts 24 hour periods crossed.
Hope this helps.
Tom Carroll
On Wednesday, January 21, 2026 at 10:07:00 AM EST, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

Erik Wienhold <ewie(at)ewie(dot)name> writes:
> On 2026-01-21 14:53 +0100, SASIKUMAR Devaraj wrote:
>> When we are migrating from sybase to postgres, we are facing issues
>> with Timestamp field format and not matching.
>> Sybase format: Jan 21 2026 5:35 PM

> I'm not familiar with Sybase.  What issues are you facing?
> But Postgres should accept this timestamp format without issue:

Yeah, I don't see a difficulty on the input side, so I'm guessing
the OP is wishing Postgres would output timestamps in that format.
Sorry, none of the built-in datestyle settings quite match that.
It's easy to replicate pretty closely using to_char():

postgres=# select to_char('Jan 21 2026 5:35 PM'::timestamp, 'Mon DD YYYY HH:MI PM');
      to_char       
----------------------
Jan 21 2026 05:35 PM
(1 row)

But wrapping all your timestamp output columns in to_char() might be
more trouble than fixing the client-side code to accept ISO format.

            regards, tom lane