Re: BUG #1993: Adding/subtracting negative time intervals

Klint Gore <kg(at)kgb(dot)une(dot)edu(dot)au> writes:
> On Tue, 25 Oct 2005 23:41:54 -0400 (EDT), Bruce Momjian
> <pgman(at)candle(dot)pha(dot)pa(dot)us> wrote:
>> test=> select
>> test-> ('2005-10-30 13:22:00-05'::timestamptz -
>> test(> '2005-10-29 13:22:00-04'::timestamptz);
>> ?column?
>> ----------
>> 25:00:00
>> (1 row)

> Is that actually the correct answer?

I'm of the opinion that the correct answer, or at least the usually
desired answer, is "1 day".

> Disregarding daylight savings, there is 25hrs between them. Once
> daylight savings is taken into account there should be 24 or 26 hours
> between them (southern/northern hemisphere respectively).

If you want the numeric "25 hours" answer, you can always extract(epoch)
from both of them and subtract. There isn't any way to get a symbolic
"1 day" answer unless we make timestamp subtraction provide it.

regards, tom lane