SQL Question, taking differences between sum of columns

Hi,

I have following table structure, tbl1( type_code varchar2(100), val integer)
having data as:

Type                    Val
---------               --------------
G1                       10
G1                        23
G2                        22
G2                        21
G3                        43
G4                        11
G4                        33
G5                        44

I would like to perform calculation such as ((sum(G1) + sum(G2)) - sum(G3)

And further more ((sum(G1) + sum(G2)) - sum(G3) * sum(G4)

Any help would be appriciated,

Thanks,
Anil G Received on Tue Jul 11 2006 - 23:13:38 CDT