Complex SQL Join

Can anyone tell me what the best method would be to achieve the following:

3 tables called A, B & C. There is a one to many relationship between A & B and also a one to many relationship between A & C. So for every A entry there will be one or more corresponding B entries and for every A entry there will be 0 (!) or more C entries.

Tables B & C both have an amount field. For each entry in A, I want to sum up all of the corresponding B amounts and all of the corresponding C amounts, but I only want to return an entry if the sum of all C amounts exceed the sum of all B amounts.

Sample data:

A Table        B Table             C Tables
=====         =====              ======
ID                ID    AMT        ID    AMT
--                ---    ------        --     ------
1                    1    100            1        100
                      1    100

2                    2    100            2        100
                                              2        100
3                    3    100

In the above example I expect to only return the following:
ID        Total B        Total C
2            100            200

Regards. Received on Fri Apr 05 2002 - 03:45:41 CST