SQL help - multiple aggregates

Hi,

I have a table cv with custid and vendid columns. Every entry represents the purchase of a product
available from a specific vendor.
Now, for a set of "interesting" vendors, I would like to select a new table
custid, c415, c983, c1256
based upon part queries
select custid, count(vendid) as c415 from cv where vendid = 415 group by custid

The only way i managed to achieve that was

select distinct custid into temp table cv1 from cv;
alter table cv1 add column c415 int;
update cv1 set c415 = part.c415 from
(select custid, count(vendid) as c415 from cv where vendid = 415 group by custid) part
where cv1.custid = part.custid;
and repeating the process for every column requested

Is there a better way (by creating an aggregate function, perhaps)

Regards
Wolfgang