sql group by clause

Question

total	vat rs	discount %
500	5	2
1000	2	2
1200	10	5

i want my result to be calculated as 

(500+5) * 2/100 =a
(1000+2)*2/100=b
(1200+10)*5/100=c
" " " " " 
""""""
""

and result = SUM(a+B+C) rs.

this is what i tried

cmd = new SqlCommand("Select (SUM(P_ttotal)+SUM(P_vatto)* (P_totdis)/100) as dis  from PRO_BILL", conn);

but it is throwing exception P_totdis is not in group by clause....
 help me in this.
any help will be appreciated 

Answer 1

i solved it 

Select Cast(SUM((O_ttotal + P_vatto) * (P_totdis / 100)) As Decimal(9,2)) As TotalDiscount From PRO_BILL

Answer 2

@Abrar that i also know, in this way i get two answers i want the whole total of (A+B+C) not (A+B) and C

Answer 3

HI, when you are using the aggregate sql function then you have to define the group by clause.

like 
cmd = new SqlCommand("Select (SUM(P_ttotal)+SUM(P_vatto)* (P_totdis)/100) as dis  from PRO_BILL group by P_totdis", conn);