On Tue, Sep 15, 2009 at 11:02:52AM -0400, Tom Lane wrote:
> David Fetter <david@fetter.org> writes:
> > I've looked through SQL:2008 (well, through
> > 6WD2_02_Foundation_2007-12.pdf), and I didn't find anything that
> > implies that the input time zone needs to be retrievable, nor
> > anything that would specify the syntax for doing so.
>
> EXTRACT()?
I see that EXTRACT() can take a time zone as input, but I don't see
anywhere that could distinguish among the following inputs, once
stored, as they have identical representations in UTC:
SELECT now() AS "West Oakland", now() AT TIME ZONE 'UTC' AS "Greenwich", now() AT TIME ZONE 'Asia/Shanghai' AS
"Pudong"; West Oakland | Greenwich | Pudong
-------------------------------+----------------------------+----------------------------2009-09-15 08:27:00.306403-07
|2009-09-15 15:27:00.306403 | 2009-09-15 23:27:00.306403
(1 row)
The way we store TIMESTAMP WITH TIME ZONE, the database converts to
UTC, discarding the input time zone in the process. SQL:2008 appears
to allow this, and doesn't appear to have a way to retrieve that input
time zone once a TIMESTAMP WITH TIME ZONE field has been stored.
Cheers,
David.
--
David Fetter <david@fetter.org> http://fetter.org/
Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter
Skype: davidfetter XMPP: david.fetter@gmail.com
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