column totals

Hi There,

I've got a situation where I need to pull profit information by product
category, as well as the totals for each branch.

Basically, something like

SELECT branch_id, prod_cat_id, sum(prod_profit) as prod_cat_profit
FROM () as b1
WHERE x = y
GROUP BY branch, prod_cat_id

Now, I also need the branch total, effectively,
SELECT branch_id, sum(prod_profit) as branch_total
FROM () as b1
WHERE x = y
GROUP BY branch_id.

Since the actual queries for generating prod_profit are non-trivial, how
do I combine them to get the following select list?

Or is there a more efficient way?

Kind Regards,
James