I'm trying to perform a subtraction calculation in ireport with two BigDecimal variables, but I have tried in every possible way and I can not.

this calculation must be done in the form, or in the query.

the calculation is very simple, I must get the negotiated quantity less the quantity invoiced, to obtain the pending amount.

in all the calculations I make, the report always returns me "NULL". Could someone help me?

It should be variable_name1.subtract(variable_name2).

I tried this too, but it did not work.

Have you confirmed both variable are indeed BigDecimal variables?

yes, both in the database and in IReport

yes