OUTER JOIN workaround... ideas?

Hey all,

I've got a situation where i would use an OUTER JOIN if i could, and
i've found a work-around, but it is significantly less than elegant.
The example:

Tables:
Category, with fields id and name;
Product, with fields id, name, quantity, and categoryId.

All products have a valid categoryId, but not all categories will have a
corresponding product.  I want a query that gives me output containing:
category.name and coalesce(sum(product.quantity), 0).  That is, i want a
summary of the number of products i have on stock for a particular
category, and if no products exist, i want a 0 (instead of a null).
Typically, i would do:

select    category.name, coalesce(sum(product.quantity), 0)
from    category, product
where    product.categoryId =* category.id

(The =* is short hand for an OUTER JOIN, giving me all rows in category,
and only those rows from product that have a valid categoryId, without
limiting the rows returned from category)

The workaround i've found (so far) is:

select    category.name,
    (select    coalesce(sum(product.quantity), 0)
     from    product
     where    product.categoryId = category.id) as quantity
from    category;

It seems like there should be a more efficient way than a sub query.
Any ideas, or am i just being picky?

Best Regards,
Jeff