Re: return MAX and when it happened - Mailing list pgsql-general

From Scara Maccai
Subject Re: return MAX and when it happened
Date
Msg-id 49243A60.3030408@yahoo.it
Whole thread Raw
In response to Re: return MAX and when it happened  (Sam Mason <sam@samason.me.uk>)
Responses Re: return MAX and when it happened
List pgsql-general
Sam Mason wrote:
> Do you really want the SUM of num1 and num2, because that makes it more
> fiddly and would be where having MAX accept a record/tuple would be
> best.  If you don't, maybe something like:
>
>   SELECT DISTINCT ON (date_trunc('day', mydate))
>       date_trunc('day', mydate), num, num1+num2
>     FROM mytab
>     ORDER BY date_trunc('day', mydate), num DESC;
>
Unfortunately, I need:

- the SUM of some values, grouped per day
- the MAX of some other value, grouped per day
- the timestamp where the MAX above happened (per day, of course)

The "num" columns are events, and sometimes I need to know not only the
amount of a certain event per day, but also WHEN the MAX of some event
happened...

I guess I have to use a Composite Type (something like "numeric,
timestamp") + user defined aggregate?








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