On Thu, Jun 2, 2011 at 3:02 PM, Jeff Davis <pgsql@j-davis.com> wrote:
> On Thu, 2011-06-02 at 18:46 +0000, Christopher Browne wrote:
>> > 1. How would the time-zone be defined in this composite? Offset from GMT?
>> > Timezone (well, link thereto) with all DST rules intact? Would "extract"
>> > need to be modified to include the ability to grab the timezone?
>>
>> That doesn't seem appropriate, because timezones are not always
>> represented by strict offsets from GMT. Some frequently-used
>> timezones represent variable offsets. ("EDT/EST", I'm looking at
>> you!)
>
> In conjunction with a specific timestamp, a timezone does strictly map
> to a single offset.
But that doesn't seem like enough, because if someone adds '1 day',
knowing the offset isn't sufficient to figure out the answer. You
have to know where the DST boundary is.
--
Robert Haas
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