I need a query in my filter to enter the {Category}. Can anyone help?

Whoa, I think I got it.

Right({Category},3) =Right(QueryString("Enter RCA,RCB,RCM,RCN,RCO,RCP,RCQ,RCS", ""),3)

Sometimes I amaze myself!

Well done!

FYI, you shouldn't need the RIGHT function on either side, as categories can only be 3 characters maximum.

Another way you could choose to tackle this is to create an additional view based on the Category code list (just the code and description), and link this to the view you are working on. You can put a filter on the Category list view to limit the list to just the 8 codes you indicated, and thus the user of the GV workspace can pick one (or more) categories to perform the link selection.