Re: Counting days ... - Mailing list pgsql-sql
From | Frank Bax |
---|---|
Subject | Re: Counting days ... |
Date | |
Msg-id | 47DA848A.9000700@sympatico.ca Whole thread Raw |
In response to | Re: Counting days ... (Frank Bax <fbax@sympatico.ca>) |
Responses |
Re: Counting days ...
(Aarni Ruuhimäki <aarni@kymi.com>)
|
List | pgsql-sql |
Frank Bax wrote: > Aarni Ruuhimäki wrote: >> 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 >> > > > #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. > Change 10,c,e to 8,10,c,e - Group 8 also does not meet your initial WHERE clause. My suggestion for WHERE clause also does not work. This might work better (although it still could be wrong): WHERE group_id = 1 AND (res_start_day BETWEEN '2007-01-01' AND '2008-12-31' OR res_end_day BETWEEN '2007-01-01' AND '2008-12-31') In case I still have it wrong, try each test group separately and you'll soon find out if the WHERE clause is correct or not.