I do not know if this is the right place to raise this, but I have a query regarding cascading combo boxes in sub forms.  I have found a suggested solution on this website, but for some reason when I have attempted to do it with my database the second combo box would ever show the full list or show nothing at all instead of reducing the selection as cascading combi boxes are meant to do.

What I need is for someone to advise what the SQL coding would be to carry out cascading on the combo box on my form, because I unfortunately am not able work it out using the information provided on this website.  This is the first time I have had to use SQL code outside of a query.

Below is what I think you may need to help with this query.
Main form  UnitDetailsNewForm
Sub form  UnitDetailAbbreviationForm this form feeds off the UnitDetailAbbreviationTable
The below are on the UnitDetailAbbreviationTable and are the only two combo boxes on the form.
First combo box  UnitDetailAbbreviationCode
Second combo box  UnitDetailAbbreviationDescription, this one should cascade when I select something in the UnitDetailAbbreviationCode box.

I have also put VBA code UnitDetailAbbreviationDescription.requery in the GotoFocus event on the UnitDetailAbbreviationCode.  I do not know if I need to do anything on the Form Events ever.

Thank you for your help in advance.