Aarni Ruuhimäki wrote:
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
Thanks Steve,
I'm not sure if I quite grasped this. It gives a bit funny results:
SELECT sum ((date_smaller(res_end_day, '2007-12-31'::date) -
date_larger(res_start_day, '2006-12-31'::date)) * group_size) AS
days_in_period,
c.country_name AS country
FROM product_res pr
LEFT JOIN countries c ON pr.country_id = c.country_id
WHERE group_id = 1 AND res_end_day >= '2007-01-01' AND res_end_day <=
'2008-12-31' group by pr.country_id, c.country_name;
days_in_period | country
----------------+--------------------
-441137 |
-30 | Germany
-28 | Estonia
60 | Bulgaria
-25003 | Russian Federation
-207670 | Suomi
256 | Ukraine
-6566 | Latvia
-280 | United States
-1889 | Switzerland
114 | Lithuania
36 | Norway
-66 | Sweden
170 | Kazakhstan
72 | Belarus
(15 rows)
Anyway, I have to rethink and elaborate the query. I know that it will usually
be on a monthly or yearly basis, but a reservation can actually be any of the
following in relation to the given (arbitrary) period:
1. start_day before period_start, end_day = period_start
2. start_day before period_start, end_day in period
3. start_day before period_start, end_day = period_end
4. start_day = period_start, end_day in period
5. start_day in period, end_day in period
6. start_day = period_start, end_day = period_end
7. start_day in period, end_day = period_end
8. start_day in period, end_day after period_end
9. start_day = period_start, end_day = period_end
10 start_day before period_start, end_day after period_end
Hmm ...
Best regards,
#6 and #9 are the same. You missed these:
a start_day before period_start, end_day before period_start
b start_day = period_start, end_day = period_start
c start_day = period_start, end_day after period_end
d start_day = period_end, end_day = period_end
e start_day = period_end, end_day after period_end
f start_day after period_end, end_day after period_end
Granted, a & f should not match where clause; but then groups 10,c,e
don't meet your where clause either. Your where clause should probably be:
WHERE group_id = 1 AND (res_start_day >= '2007-01-01' AND res_end_day <=
'2008-12-31')
Are you sure that your database does not have any rows where start_day
is after end_day? These rows could certainly skew results.
I would suggest that you identify a few rows that meet each of these
conditions. Change the where clause to select rows in one group at a
time. You might consider using a unique row identifier in where clause
during these tests to make sure you are processing the rows you think
you are. When all test cases work properly; then run your generalized
query again.
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