MySQL Forums :: Newbie :: double join in update?

Hello everyone,
have a brain task, cant get in, need help.

have 3 table with next fields:

`categories`:
category_id category_name

`product_categories`:
product_id category_id

`products`:
product_id product_name agregate_field


Need update `products` and set every
agregate_field=concat(category_name,product_name).

Is it possible in 1 query?

Have a practice with subqueries but with no success.
have no practice with joins.
Thanks in advance.