Re: Get different sums from the same table in one query

On 08/10/2007, A. Kretschmer <andreas(dot)kretschmer(at)schollglas(dot)com> wrote:
>
> am Mon, dem 08.10.2007, um 12:49:04 +0200 mailte Dani Castaños folgendes:
> > Hi all!
> >
> > I want to put this three queries in only one... Take a look that the
> > only thing that changes is the message_type_id. Any suggestions??
>
> Yes, no problem, You can use UNION (ALL) for such.

Not sure thats what he wants at all. Anyway Union all is going to produce a
very slow way of doing this needing to go back to the data 3 times where as
this only goes once.

SELECT TO_CHAR( statistics_date, 'DD/MM/YYYY') AS date_in,
sum(case when message_type_id in (4,5) then total_num_messages else 0 end)
as fourorfive,
sum(case when message_type_id in (6) then total_num_messages else 0 end) as
six,
sum(case when message_type_id in (21) then total_num_messages else 0 end) as
twentyone
FROM statistics_daily
WHERE statistics_date = CURRENT_DATE
AND telecom_operator_id <> 0
AND telephone_number IN ( $numbers )
GROUP BY date_in

You may have to play to get exactly what you want but here worse case your
only doing one scan of the table not three... You may want to use views to
simplify things.

Peter Childs

Andreas
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