Sum multiple values for the same Invoices
I have a dataset that contains multiple rows of orders. I got an account number that represents the same client but the same client can have multiple orders. I would like to create a transformation that would SUM revenues and expenses that are all assigned to the same account number that represent 1 unique customer. In other words I want to sum up some values in different rows based on the same Account number. (I could do that from analyzer but I would really like to know how to create such transformation on the ETL level.