Message-ID: <46ED5DBF.1030303@Sheeky.Biz>
Date: Mon, 17 Sep 2007 02:15:51 +0930
From: Shane Ambler <pgsql@Sheeky.Biz>
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To: Andreas Joseph Krogh <andreak@officenet.no>
CC: pgsql-sql@postgresql.org, Andreas Kretschmer <akretschmer@spamfence.net>
Subject: Re: Format intervall as hours/minutes etc
References: <200709161300.53257.andreak@officenet.no>
	<20070916111427.GA13886@KanotixBox>
	<200709161327.16989.andreak@officenet.no>
In-Reply-To: <200709161327.16989.andreak@officenet.no>
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Andreas Joseph Krogh wrote:
> On Sunday 16 September 2007 13:14:27 Andreas Kretschmer wrote:
>> Andreas Joseph Krogh <andreak@officenet.no> schrieb:
>>> Hi all. Any hint on how to format this interval as number of hour/seconds
>>> etc? select age('2007-09-22 17:00'::timestamp, '2000-02-20
>>> 18:00'::timestamp); age
>>> -------------------------------
>>>  7 years 7 mons 1 day 23:00:00
>> You can use extract(epoch, from ...) like this:
>>
>> test=*# select extract(epoch from '2007-09-22 17:00'::timestamp) - extract
>> (epoch from '2000-02-20 18:00'::timestamp); ?column?
>> -----------
>>  239407200
>> (1 row)
>>
>> Now you can calculate the hours and so on.
> 
> Yes, this works fine for dates >= 1970, but I'm looking for a more general 
> solution which takes an arbitrary interval as input. The reason why I'm using 
> PG to calculate this is 'cause it takes 25/23 hour days, leapyears etc. into 
> account when calculating intervals.

Is that all you use it for?? ;-)

You may want to add the timezone to get the effect of daylight savings.

postgres=# select age('2007-03-25 7:00:00'::timestamptz, '2007-03-25 
1:00:00'::timestamptz);
    age
----------
  06:00:00
(1 row)

postgres=# select age('2007-03-25 7:00:00+9:30'::timestamptz, 
'2007-03-25 1:00:00+9:30'::timestamptz);
    age
----------
  05:00:00
(1 row)


I haven't used intervals much so I may be missing something.

I get the idea you want the interval to be expressed as 2,765 days and 
23 hours or 66,383 hours, which I think would be useful (more so for 
shorter intervals).

I am thinking the exact function you are after isn't there - from what I 
can find a larger interval is always given as x years y months z days... 
which is why extracting the epoch is the easiest point to start your calcs.

Maybe this can be a feature request - functions to give an interval in 
total number of days/hours/minutes instead of years months days


-- 

Shane Ambler
pgSQL@Sheeky.Biz

Get Sheeky @ http://Sheeky.Biz