Hi!
I have this problem:
I've got the form, which is editing a row in the table.
I have the "number of available" field which takes a value from the table and field not associated with the table "how much to spend" in which I can type a number.
I want by typing in the box "how much to spend" number, count the value of the field "Number of available"= "Number of available" - "how much to spend"
Alternatively, this can happen when you save / close the form.
Has anyone any idea?