Re: work hour calculations

am Wed, dem 05.09.2007, um 13:45:46 +1000 mailte novice folgendes:
> Hello All,
>
> SELECT notification_time, finished_time, sum(finished_time -
> notification_time) as actual
> FROM log
> GROUP BY notification_time, finished_time;
>
> gives me:
>
> notification_time | finished_time | actual
> ------------------------+------------------------+-----------------
> 2007-07-06 15:50:00+10 | 2007-07-09 07:10:00+10 | 2 days 15:20:00
> 2007-07-07 12:30:00+10 | 2007-07-09 07:20:00+10 | 1 day 18:50:00
>
>
> How can write a query to calculate the duration using custom work
> hours which is Monday 7am / Friday 5pm?
>
> The result I'm expecting for the above to be
>
> notification_time | finished_time | actual
> ------------------------+------------------------+-----------------
> 2007-07-06 15:50:00+10 | 2007-07-09 07:10:00+10 | 00:20:00
> 2007-07-07 12:30:00+10 | 2007-07-09 07:20:00+10 | 00:20:00

You can write a function. Calculate for every day between
notification_time and finished_time this timestamps for every day. I
mean, for instance your first row:

2007-07-06 15:50:00+10 2007-07-07 00:00:00+10
2007-07-07 00:00:00+10 2007-07-08 00:00:00+10
2007-07-08 00:00:00+10 2007-07-09 00:00:00+10
2007-07-09 00:00:00+10 2007-07-09 07:20:00+10

Now check, if the first timestamp are a working day (select
extract('dow' from '2007-07-06 15:50:00+10'::timestamptz)). If so, than
calculate the working-time and adds all.

A little function for you:

<--- cut
create or replace function intersect_time (IN start timestamptz, IN stop timestamptz, IN w_start timestamptz, IN w_end timestamptz, OUT duration interval) as $$
declare
_s1 alias for $1;
_e1 alias for $2;
_s2 alias for $3;
_e2 alias for $4;
_start timestamptz;
_end timestamptz;

begin

if _s1 < _s2 then
_start := _s2;
else
_start := _s1;
end if;

if _e1 < _e2 then
_end := _e1;
else
_end := _e2;
end if;

if _start < _end then
duration := _end - _start;
else
duration := '0'::interval;
end if;

return;

end;
$$language plpgsql;

--- cut

A simple test:

Only the first and the last are working days, so we call the function
for this rows:

test=*# select intersect_time('2007-07-06 15:50:00+10'::timestamptz,'2007-07-07 00:00:00+10'::timestamptz, '2007-07-06 07:00:00+10'::timestamptz, '2007-07-06 17:00:00+10'::timestamptz);
intersect_time
----------------
01:10:00
(1 row)

test=*# select intersect_time('2007-07-09 00:00:00+10'::timestamptz,'2007-07-09 07:10:00+10'::timestamptz, '2007-07-09 07:00:00+10'::timestamptz, '2007-07-09 17:00:00+10'::timestamptz);
intersect_time
----------------
00:10:00
(1 row)

test=*# select '01:10:00'::interval + '00:10:00'::interval;
?column?
----------
01:20:00
(1 row)

Hope that helps, Andreas
--
Andreas Kretschmer
Kontakt: Heynitz: 035242/47150, D1: 0160/7141639 (mehr: -> Header)
GnuPG-ID: 0x3FFF606C, privat 0x7F4584DA http://wwwkeys.de.pgp.net