Re: Why extract( ... from timestamp ) is not immutable? - Mailing list pgsql-general

From hubert depesz lubaczewski
Subject Re: Why extract( ... from timestamp ) is not immutable?
Date
Msg-id 20120125165750.GA28055@depesz.com
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In response to Re: Why extract( ... from timestamp ) is not immutable?  (Adrian Klaver <adrian.klaver@gmail.com>)
Responses Re: Why extract( ... from timestamp ) is not immutable?  (Adrian Klaver <adrian.klaver@gmail.com>)
List pgsql-general
On Wed, Jan 25, 2012 at 08:54:44AM -0800, Adrian Klaver wrote:
> > Personally, I think that extract(epoch from timestamp) should assume
> > that the timestamp is UTC.
>
> What if it isn't?

then you can always correct it with "at time zone 'some specific time
zone'"

but you can't correct it the other way.

> > Or that there should be a way to do it - by "it" i mean - extract epoch
> > value from timestamp value in immutable way.
>
> Have a timezone value on the timestamp. If the data you are working with is
> stored as timestamp with time zone then the timestamps represent a point in
> time.

I do have. But you can't have index on epoch from timestamptz.
and while you can have iundex on epoch from timestamp, it is not
correct.

depesz

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