I need an expression to help me sum customer transactions. In my table i have a list of customers. They have a unique id (Customer Number). The table shows all transactions done that month PER customer. I need a virtual column that sums the transactions per customer.
Then i need to reference another table that shows the same Customers, customer number - their balance. I need to calculate (while referencing between these tables):
Customer Balance / Total of transactions (from the first table i need to total) - PER CUSTOMER