I've given this a go, but it seems very willing to
include the items in the other query, and very unwilling to
exclude them. I've attached a cut down sample of my database into this reply, maybe if some context is brought in, it may help in solving the problem.
There are three forms in the database, opening up FrmChooseComponents is your starting point. Here, a main form is shown with a subform (it shows harness models, and the batches of stock used to make them). This is based on three tables; one for the harnesses, one for the components, and one to link them.
Clicking on the "choose batch" button brings up the last table, showing a selection of stock that can be associated with the harness. It is currently based on a simple query, that only shows components that are ticked as "available", from their table.
When the "use" button is clicked, the "GI Number" is transferred into the main subform, and a new association is made, creating a record in the linking table. This is where the problem lies, because if you look at the GI numbers, you'll notice that there are already records containing these in the subform. If you try to select these, you get a nasty error message about duplicate values. I would like to restrict the query so that when the selection form opens up, these records do not appear.
Problem.zip
This link should work, the file is a little to large to upload. I hope the explanation isn't too long winded, any help would be greatly appreciated!