Re: Top five challenges - Mailing list pgsql-advocacy

From Adrian Klaver
Subject Re: Top five challenges
Date
Msg-id 4D790EFE.2070602@gmail.com
Whole thread Raw
In response to Re: Top five challenges  (silly sad <sad@bestmx.ru>)
Responses Re: Top five challenges
List pgsql-advocacy
On 03/10/2011 09:15 AM, silly sad wrote:
> On 03/10/11 20:07, Adrian Klaver wrote:
>> On 03/10/2011 08:53 AM, silly sad wrote:
>>
>>
>>>>
>>>> Well, 'epoch' clearly is a point in time with the hour being midnight at
>>>> GMT, so I don't see a problem with epoch making such an adjustment:
>>>
>>>
>>> great! the flexible epoch!
>>>
>>> when do want to point an epoch to?
>>> just set timezone and enjoy.
>>>
>>
>> I am not sure what your point is.
>
> my point is:
>
> SELECT extract('epoch' from 'epoch'::timestamp);

Simplest explanation is you are comparing a time zone aware datetime
'epoch' to an unaware one 'epoch'::timezone.  The second one, since it
is not anchored to a time zone is taken to be local time and the result
you get is the interval in seconds between the two.

Try:

test=> SELECT extract(EPOCH  from 'epoch'::timestamptz);
  date_part
-----------
          0

or

test=> SELECT extract(EPOCH  from 'epoch'::timestamp at time zone 'utc');
  date_part
-----------
          0


--
Adrian Klaver
adrian.klaver@gmail.com

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