Fredg, The query will ultimately be used for reporting purposes.
You'll need to use a form to do this.
Let's assume it is a CustomerID number you need as criteria.
Make a new unbound form.
Add a combo box that will show the CustomerID field.
Make sure the Combo Box Bound Column is the
CustomerID field.
Add a command button to the form.
Code the button's Click event:
Me.Visible = False
Name this form "ParamForm"
Code the Report's Record Source Query's CustomerID field criteria
line:
forms!ParamForm!ComboBoxName
Code the Report's Open Event:
DoCmd.OpenForm "ParamForm" , , , , , acDialog
Code the Report's Close event:
DoCmd.Close acForm, "ParamForm"
Run the Report.
The report will open the form.
Find the CustomerID in the combo box.
Click the command button.
The Report will display just those records selected.
When the Report closes it will close the form.