Nothwind orders total cost box

[John thomas]

In the North wind database
In the orders box subform
they have a totals cost box underneath how do they do this

 

[AccessMSSQL]

go to design view and check the control source property of that box that has the subform total. It's probably using a sum function: Sum(Cost). That box could be in the footer section of the subform. If the box is outside the subform then the field is probably referencing a totals control within the subform - something like: Forms!MainForm!SubForm.Form!TotalSum