>Ok, thanks.
>But, I don't want to read the table again with a Select, I try to get a results with data in the grid, because the recordsource of a grid is an alias that is an child table. Do you know if it is posible? Because the records in the grid are less than table

You have Where clause of Select which will do this job, something like
Select SUM(... From Mytable Where ParentId=Parenttable.Id Into ....