The contents of a dropdown list box can be filtered to display only a subset of values by adding a WHERE clause in the Query Wizard.
Step 1: In the Page Layout Spreadsheet, select a dropdown list box control.
Step 2: In the Data Sources tab, select the appropriate query and open the Query Wizard (Edit…).
Step 3: In the Query Wizard, add a new WHERE clause containing a formula that restricts the contents, e.g.:
= “UK”
In this example, the values are restricted to only “UK” customers.
Step 4: Build and run your application.