Question : Summing amount using a aggregate function in a query

I am trying to sum a column and enter the result in a textbox in the main form.   My design has a main form with several subforms.  The subform is used to list the details of items.  

I have two querries, one to list the details and another to arrive at the total usiing the SUM aggregate and group by.  My problem is that I don't know how to post the sum into the main form.  At this time I am getting a #NAME error in the total textbox.

Answer : Summing amount using a aggregate function in a query

If your data are source of your form (subform), you can add field to the form (or subform) footer with value:
=sum([Mydata])