Subtract ListBox items in field of a table

[Electricks21]

Hello guys.



I have a form with a textbox, listbox and a button.
my textbox is based on one of my tables, and when I enter a value (which is saved in my table) in my textbox and press enter, certain values in my table goes to my listbox, and my listbox will just additem whenever I do same thing in my textbox all overagain.
Now here's the question,
how can I subtract listbox.column(1) items in my table field "Item_Quantity" where my Listbox.column(0) is equal to my table field "Item_Description".

My Listbox column count property = 4
Row source type = value list


Thank you in advance guys .

[June7]

Sounds like you are storing calculated aggregate data. This is usually a bad idea. Aggregate data should normally be calculated when needed, not stored. Review http://allenbrowne.com/AppInventory.html

[Electricks21]

Oh no. tsk. think gotta change my process. anyway thanks for the info june7. (;