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

Thanks for all this discussion, fixing, etc. I'm currently having
"issues" getting postgres' date/time functions to do what I want. You
have obviously spotted some of the reasons for this.

Many of my issues disappear when I use 8.1, but it's still in beta. Is
it safe for me to use 8.1 in production, if I don't use any of the new
features? If not, would it be possible to backport these date/time
changes to 8.0 so that my program can operate correctly before 8.1 is
finished beta? I can do this backporting myself if someone can point me
to the relevant files. (I'm sure I can work it out myself if necessary,
but I'm a little busy at the moment).

BTW, Postgres' date functions are *great* except for these minor
problems. The best I've ever used.

Thanks!
Nicholas

Klint Gore wrote:

>On Tue, 25 Oct 2005 13:28:00 -0400, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
>
>>regression=# select '2005-10-29 13:22:00-04'::timestamptz + '1 day'::interval;
>> ?column?
>>------------------------
>> 2005-10-30 13:22:00-05
>>(1 row)
>>
>>regression=# select '2005-10-30 13:22:00-05'::timestamptz - '2005-10-29 13:22:00-04'::timestamptz;
>> ?column?
>>----------------
>> 1 day 01:00:00
>>(1 row)
>>
>>ISTM that given the former result, the latter calculation ought to
>>produce '1 day', not something else.
>>
>>
>
>Would the '1 day' result know it was 24 hours or be the new 23/24/25
>hour version of '1 day'?
>
>If it was the new version, could you get the original values back?
>i.e. what would be the result of
>select
>('2005-10-29 13:22:00-04'::timestamptz +
>('2005-10-30 13:22:00-05'::timestamptz -
> '2005-10-29 13:22:00-04'::timestamptz)) at time zone 'EST';
>
>klint.
>
>+---------------------------------------+-----------------+
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>+---------------------------------------+-----------------+
>
>