In the raw data, I have product, brand, month, sales volume, cost, qty. I add margin (i.e., sales volume - cost) as a custom column on top of the raw data in a Question, and get a summation of the margin in the summarize field. I can get a pivot table with brand as column, month as row, and sum of margin as value, but how can I get a pivot table with brand as column, month as row, and margin percent (i.e., sum of margin / sum of sales volume) as value?
If I get add the margin percent as a custom field, it is not pivot-table.