Re: need nelp with aggregate functions

ok, I did: SELECT count(DISTINCT c.cliente_id) as qtd_client,count(cm.cm_id)
as qtd_computers
GREAT. It works.
Please, explain me why and how it works, I wanna learn and do by myself next
time :)

2009/11/18 Oliveiros C, <oliveiros(dot)cristina(at)marktest(dot)pt>

> Try substituting the SELECT count(c) as qtd_client,count(cm) as
> qtd_computers
>
> by
>
> SELECT count( DISTINCT c.cliente_id) as qtd_client,count(/* put here the
> primary key of the computer table */ ) as qtd_computers
>
> Then tell me if it output what you want
>
> Best,
> Oliveiros
>
>
> ----- Original Message -----
> *From:* Another Trad <anothertrad(at)gmail(dot)com>
> *To:* pgsql-sql(at)postgresql(dot)org
> *Sent:* Wednesday, November 18, 2009 4:55 PM
> *Subject:* [SQL] need nelp with aggregate functions
>
> The DB structure is in attachment.
> I with the number of clients and the number of computers that have
> processors with "manufacturer" = "INTEL" and "speed" = "2GB"
> I am trying:
>
> select count(c) as qtd_client, count(cm) as qtd_computers
>
> from cliente c
> inner JOIN computer cm on (c.cliente_id = cm.cliente_id)
> inner join processor p on (cm.processor_id = p.processor_id)
> inner join speed s on (s.speed_id = p.speed_id)
> INNER JOIN manufacturer m on (p.manufacturer_id=m.manufacturer_id)
>
> where m.manufacturer = 'INTEL'
> and s.speed = '2GB'
>
> but is not working
> anyone can help me?
>
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