Assuming you have a table which lists all possible activities, with one activity per row and no duplicates, you need to do a left outer join between activities and your query result. That will generate a resultset that has at least one row for every row in activities, with nulls in all the columns coming from the query for rows that don't have a match. Then use coalesce to turn null into 0. Something like this:
select a.activity_id, coalesce(q.total, 0) as total
from activities a left outer join
(select fa.activity_id, count(fa.activity_id) as total from foo_activity fa
where fa.created between '01/01/2011' and '01/08/2011'
group by 1) q on a.activity_id = q.activity_id
order by a.activity_id
If you don't have an activities table with one row per activity, just replace the activities table in that query with another query - select distinct activity_id from foo_activity
On Fri, Feb 11, 2011 at 10:46 AM, Aaron Burnett
<aburnett@bzzagent.com> wrote:
Hi,
I'm just drawing a blank entirely today and would appreciate some help on
this.
The long and short; there are 12 distinct activities that need to be queried
on a weekly basis:
SELECT count(activity_id), activity_id
FROM foo_activity
WHERE created >= '01/01/2011' and created < '01/08/2011'
GROUP BY 2
ORDER BY 2;
It gives me this answer, which is correct:
count | activity_id
-------+---------------------
1502 | 1
11 | 2
2 | 3
815 | 4
4331 | 7
30 | 9
1950 | 10
7 | 11
67 | 12
But what I need to see is if there are no activities for the particular
activity_id that week, that it lists the count as 0 and lists the
activity_id associated like this:
count | activity_id
-------+---------------------
1502 | 1
11 | 2
2 | 3
815 | 4
0 | 5
0 | 6
4331 | 7
0 | 8
30 | 9
1950 | 10
7 | 11
67 | 12
Thanking you in advance for any help on this. The caffiene seems to be not
working well today.
Aaron
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