Re: Problem in age on a dates interval

Luis,

wow.... at first I thought I had my head around a leap
year problem so I advanced your query a year....

testbed=# SELECT age('2005-05-14
16:00'::timestamp,'2005-02-18 16:00'::timestamp);
age
----------------
2 mons 24 days
(1 row)

testbed =# SELECT '2005-02-18 16:00'::timestamp +'2
mons 24 days'::interval;
?column?
---------------------
2005-05-12 16:00:00
(1 row)

I just thought I would let you know it can get
worse..... :) I don't know how daylight savings time
is playing this problem... but I didn't expect the
problem to grow like that.

Ted

--- Luis Sousa <llsousa(at)ualg(dot)pt> wrote:
> Hi all,
>
> I'm using PostgreSQL 7.3.3 on i386-pc-linux-gnu,
> compiled by GCC gcc
> (GCC) 3.3 (Debian), and I don't understand the
> results of the following
> queries:
>
>
> SELECT age('2004-05-14 16:00'::timestamp,'2004-02-18
> 16:00'::timestamp);
> age
> ----------------
> 2 mons 25 days
>
> SELECT '2004-02-18 16:00'::timestamp+'2 mons 25
> days'::interval;
> ?column?
> ---------------------
> 2004-05-13 16:00:00
>
> In this case, the age from 2004-05-14 16:00 to
> 2004-02-18 16:00 is 2
> mons 25 days, but if I add the age to the initial
> date, it returns one
> day less!?
>
> SELECT age('2004-05-26 16:00'::timestamp,'2004-02-18
> 16:00'::timestamp);
> age
> ---------------
> 3 mons 8 days
>
> SELECT '2004-02-18 16:00'::timestamp+'3 mons 8
> days'::interval;
> ?column?
> ---------------------
> 2004-05-26 16:00:00
>
> Here, the age between 2004-05-26 16:00 and
> 2004-02-18 16:00 is 3 mons 8
> days, and this interval added to the initial date
> gives the correct result!!
>

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