SQL select query using Joins with aggregate counts - sql

Question

I have a table with the following fields:
tickets: id, createddate, resolutiondate
A sample set of data has:
jira=# select * from tickets;
id | createddate | resolutiondate
---------+-------------+----------------
ticket1 | 2020-09-21 | 2020-10-01
ticket2 | 2020-09-22 | 2020-09-23
ticket3 | 2020-10-01 |
ticket4 | 2020-10-01 | 2020-10-04
ticket5 | 2020-10-01 |
ticket6 | 2020-10-01 | 2020-10-07
(6 rows)
jira=#
I would like to create a query which reports:
Week: Issues Created: Issues Resolved
I can do the two separate queries:
# select date_trunc('week', createddate) week, count(id) created
from tickets
group by week
order by week desc
;
week | created
------------------------+---------
2020-09-28 00:00:00+00 | 4
2020-09-21 00:00:00+00 | 2
(2 rows)
# select date_trunc('week', resolutiondate) week, count(id) resolved
from tickets
where resolutiondate is not NULL
group by week
order by week desc
;
week | resolved
------------------------+----------
2020-10-05 00:00:00+00 | 1
2020-09-28 00:00:00+00 | 2
2020-09-21 00:00:00+00 | 1
(3 rows)
However - I can not figure out how (with a join, union, sub-query, ...?) to combine these queries into a combined query with the appropriate aggregations.
I'm doing this is Postgres - any pointers would be appreciated.

Answer 1

Performing a union before aggregating values may work here eg
select week,
count(id_created) as created,
count(id_resolved) as resolved
from (
select date_trunc('week', resolutiondate) week, NULL as id_created, id as id_resolved from tickets UNION ALL
select date_trunc('week', createddate) week, id as id_created, NULL as id_resolved from tickets
) t
group by week
order by week desc
Let me know if this works for you.