want to use the result of an sql query in another query (2 replies)

Hi
i wish i get a response for my question
i have one table that contains these fields
cell_id/ NodeB_id / Credit/
i want to make max(credit) group by cell_id that is very simple:

SELECT MAX(Credit) FROM table GROUP BY Cell_id

but after that i want to make the sum of these max group by NodeB_id
how to do that ? i have to use query cascades ? and how to do it ?

plz i really need this query to continue my project