Sorry, my bad, I meant 5 days x 4 persons = 20 person-days. From 10 to 15 it
is 5 'days' ? Arrival 10th and departure 15th makes 5 'nights' or 'days',
whatever one might call it, statistical accommodation units.
Likewise, res_id x, start_day some time before Feb 08, end_day 2008-02-16 for
a statistical period Feb 08 makes 16 units ?
First, to simply establish upper and lower bounds,
date_larger/date_smaller seems a lot easier - ie. for February inclusive
dates:
select
sum (
((date_smaller(res_end_day, '2008-02-29'::date)
- date_larger(res_start_day, '2008-02-01'::date))::int + 1) * group_size
) as person_days;
Check my work, but I think the sum part of the query simply becomes:
sum (
(
date_smaller(res_end_day, '2008-02-29'::date) -
date_larger(res_start_day, '2008-01-31'::date)
) * group_size
)
Basically remove the "+1" so we don't include both start and end dates
but move the start base back one day so anyone starting prior to Feb 1
gets the extra day added.
Cheers,
Steve
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