Thomas Lockhart writes:
> Typical date/time arithmetic resolves to an absolute time or interval.
> In those cases, *qualitative* quantities such as years and months are
> resolved to a specific absolute interval at the time of calculation.
>
> The age() functions *preserve* the qualitative fields
Thomas Lockhart writes:
> > b) date substraction not implemented at all (it does date - integer)
>
> No, and changing what it *does* do has ramifications.
Okay, I see there's 'date - date' after all. But 'date - date' should
still return some kind of time interval, not an integer. Of course
ch
> ISTM that this is more a result of
> a) timestamp subtraction not implemented per spec
Maybe. But it is implemented consistantly, and is more functional and
capable than the brain-damaged SQL9x spec (c.f. Date and Darwen) asks.
> b) date substraction not implemented at all (it does date - inte
Thomas Lockhart writes:
> The age() functions *preserve* the qualitative fields year and month. So
> you see the difference in results:
>
> lockhart=# select age('today', '1957-06-13');
> -
> 43 years 9 mons 28 days
>
> lockhart=# select timestamp 'today' - timestamp '195
> As you see in one of the examples I posted, it does not preserve years and
> months. What exactly does that mean anyway? Simple subtraction also
> preserves years and months, as I see it.
OK, so there is a documentation problem, since the functions do exactly
what they claim!
What do you mea
> Thomas Lockhart writes:
>
> > Why do you have a problem with the age() function? It *does* behave
> > differently than date subtraction, as explicitly mentioned in the docs
> > (preserving years, etc etc).
>
> As you see in one of the examples I posted, it does not preserve years and
> months.
Thomas Lockhart writes:
> Why do you have a problem with the age() function? It *does* behave
> differently than date subtraction, as explicitly mentioned in the docs
> (preserving years, etc etc).
As you see in one of the examples I posted, it does not preserve years and
months. What exactly d
Thomas Lockhart writes:
> I notice that the docs have commented-out all mention of the age()
> functions, with the note that "These two functions don't seem to do what
> it says here, or anything reasonable at all for that matter."
>
> ??
>
> How did we conclude that, and how could these be confu
> >
> http://www.postgresql.org/mhonarc/pgsql-hackers/2001-02/msg00550.html
OK, so that narrows down the list of suspects ;)
Why do you have a problem with the age() function? It *does* behave
differently than date subtraction, as explicitly mentioned in the docs
(preserving years, etc etc). Wo
