sum of agreggates in one SELECT?

Hello,

I have the following query/result:

auction=# select max(b.lot) as quantity,max(b.price) as price,p.login from bid b, person p where b.auction_id = 84 and p.id = b.person_id group by p.login order by max(price);
quantity | price | login
----------+-------+-----------
1 | 5000 | papy
12 | 5750 | cunctator
8 | 6000 | vindex
(3 rows)

Now I would like to sum() all results from the quantity column and
return it with one SELECT statement. Is that possible?

I am trying:

auction=# select sum(b.lot) from bid b, person p where b.auction_id = 84 and p.id = b.person_id ;
sum
-----
52
(1 row)

But this is wrong because it sums all quantities. I don't know how to
apply a valid WHERE clause in that case.

Thanks in advance for any help, cheers,

--
Louis-David Mitterrand - ldm(at)apartia(dot)org - http://www.apartia.org