I have faced some "complicated" query, like:
with q1 as (
select w.entity_id, p.actionable_group, p.error_type
from issue_analysis p
join log l on p.id = l.issue_analysis_id
join website w on l.website_id = w.id
where l.date >= '2016-06-01'
group by 1, 2, 3
),
q2 as (
select w.entity_id, p.actionable_group, p.error_type
from issue_analysis p
join log l on p.id = l.issue_analysis_id
join website w on l.website_id = w.id
where l.date >= '2016-06-01'
group by 1, 2, 3
having count(1) = 1
)
And tried to
SELECT q1.entity_id, count(q1.entity_id), count(q2.entity_id)
from q1, q2
group by 1
order by 1
but result provides for me a "wrong" data, cause it's not really contains both counts...
could you please describe the most "cleaner" way to solve such issue without a lot of nested queries?
if it may be helpful - q2
is similar to q1
but with having count(1) = 1
at the end.
P.S. Documentation link will be fine is the answer is simple.
You are, no doubt, getting a Cartesian product and this affects the aggregation. Instead, aggregate before doing the joins:
select q1.entity_id, q1_cnt, q2_cnt
from (select q1.entity_id, count(*) as q1_cnt
from q1
group by q1.entity_id
) q1 join
(select q2.entity_id, count(*) as q2_cnt
from q2
group by q2.entity_id
) q2
on q1.entity_id = q2.entity_id;