Group By Dynamic Ranges in SQL (cockroachdb/postgres) - sql

Question

I have a query that looks like
select s.session_id, array_agg(sp.value::int8 order by sp.value::int8) as timestamps
from sessions s join session_properties sp on sp.session_id = s.session_id
where s.user_id = '6f129b1c-43a6-4871-86f6-1749bfe1a5af' and sp.key in ('SleepTime', 'WakeupTime') and value != 'None' and value::int8 > 0
group by s.session_id
The result would look like
f321c813-7927-47aa-88c3-b3250af34afa | {1588499070,1588504354}
f38a8841-c402-433d-939d-194eca993bb6 | {1588187599,1588212803}
2befefaf-3b31-46c9-8416-263fa7b9309d | {1589912247,1589935771}
3da64787-65cd-4305-b1ac-1393e2fb11a9 | {1589741569,1589768453}
537e69aa-c39d-484d-9108-2f2cd956d4ee | {1588100398,1588129026}
5a9470ff-f930-491f-a57d-8c089e535d53 | {1589140368,1589165092}
The first column is a unique id and the second column is from and to timestamps.
Now I have a third table which has some timeseries data
records
------------------------
timestamp | name | value
Is it possible to find avg(value) from from records in group of session_ids over the from and to timestamps.
I could run a for loop in the application and do a union to get the desired result. But I was wondering if that is possible in postgres or cockroachdb

Answer 1

I wouldn't aggregate the two values but use two joins to find them. That way you can be sure which value belongs to which property.
Once you have that, you can join that result to your records table.
with ranges as (
select s.session_id, st.value as from_value, wt.value as to_value
from sessions s
join session_properties st on sp.session_id = s.session_id and st.key = 'SleepTime'
join session_properties wt on wt.session_id = s.session_id and wt.key = 'WakeupTime'
where s.user_id = '6f129b1c-43a6-4871-86f6-1749bfe1a5af'
and st.value != 'None' and wt.value::int8 > 0
and wt.value != 'None' and wt.value::int8 > 0
)
select ra.session_id, avg(rc.value)
from records rc
join ranges ra
on ra.from_value >= rc.timewstamp
and rc.timestamp < ra.to_value
group by ra.session_id;