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help / color / mirror / Atom feedFrom: dfgpostgres <[email protected]>
To: [email protected]
Subject: How to select avg(select max(something) from ...)
Date: Tue, 18 Feb 2025 15:56:27 -0500
Message-ID: <CAAcmDX8Xs5+NbSV1UGUsj06yQpC=wYj_FOfTMZNvFe6uXDTqcw@mail.gmail.com> (raw)
Hi:
psql 15.3
I have a table with sets of observations, each set sharing an id.
I want to get the average of the max of each set.
id | val
-----------
1 5.0
1 4.3
1 3.8
2 4.8
2 6.0
2 2.9
3 4.1
3 4.4
3 8.0
So I want the avg of the max of the set where id=1 (5.0), where id=2 (6.0),
where id=3 (8.0) ~= 6.33...
I tried this...
select
avg(x.maxsz)
from
dvm.dvm_events d,
(select cast(max(size_g) as int) as maxsz
from dvm.wa_du_profile_data
where dvm_id=d.dvm_id) x
where
d.project='foo' and
<more conditions on d>
It doesn't like that reference to "d.dvm_id) in that subquery.
reply
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