Fields not Aggregated

Hi, I have two table with some value. Join this table in left mode.

First table contain one field thats is fixed. Second table have same rows and a field that i need sum and compare to first table.

But when I join this table, numeric fields are in aggregation and I can't work with not aggregation formula.

In particular I need to compare first table field to second table fields sum.

How I can do it?

I need also show it into a Istogram graph.

thanks