On Sun, Feb 18, 2007 at 09:19:43PM +0900, Michael Glaesemann wrote:
> >What I don't understand, however, is exactly *why* date_trunc is
> >not immutable ?
>
> I believe it's because the result of date_trunc depends on the time
> zone setting for the session.
...
> So, given the same arguments, ('day', and current_timestamp),
> date_trunc is returning two different results. (Casting to date has
> the same issue.)
Ah, I see. That makes sense.
Now, if I'd write a
date_trunc_utc(precision, timestamp with time zone)
which converts input timestamps to UTC I could fairly safely
mark that IMMUTABLE, no ?
Karsten
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