SUM 2 columns when the value of the third column is DISTINCT

Question

Hello everyone,

I have a dataset like this :

ID	TAX	SubTotal
1	10	2
1	10	2
1	10	2
2	5	3

I want a calculated field that can return for each distinct ID the sum of subTotal and Tax.

So I'll here get for ID = 1 a result of 12 and NOT 36.

Thank you all !