How to summarize value by unique and detail dimension's value

[ameliafadhillah]

Hi, I am having trouble trying to summarize the promo contribution (Revenue Promo Product) value to the total sales (Revenue All Product) at the promo period when the name of campaign is the same but month's different. The data structure is as attached. I have tried using the AVG to get the monthly total sales but the value is not valid because the total sales are repeated based on the product row details. Is there a way to summarize it based on a unique date period first and then sum it up by month?

[sam8]

It's difficult (maybe impossible?) to show subtotals in a Looker Studio table.

What about making a second table that only has the dimensions for campaign and month, with the metric for total sales? This should give you the values you need, and you can display both tables on one report.