Query Question

Here is a simple query question that has me stumped.

I have a database that contains the information on vehicle maintenance
costs. When a repair is done to a vehicle, the tag number and the amount
of the repair is recorded.

table structure runs as follows:

id serial
po varchar(12)
veh_no varchar(8)
cost real
comments varchar(30)

I would like to be able to do a query in which I can list all of the
vehicles and a totalization of the costs, e.g. list one vehicle number, and
the sum of costs for that vehicle. Because there are numerous entries for
each vehicle I know that some part of the query will have to include
"distinct veh_no" so that only one output for each vehicle is listed.

I have figured out a way to do this with Perl, but it takes two selects,
and I would prefer to do this with just one.

Any hints or ideas?

Thanks in advance for any assistance.

Regards - Bob Kruger