Search form getting wrong results

[Ruegen]

I have a table of states related to a table of schools,

each school has a state



on a search form I have the query Nz([Forms]![frmSchoolSearch]![cmbState],[tblSchools]![StateID]) under the StateID

This is so that if nothing in the combobox shows all the schools show, if they select a state from the combo box on the form then it filters the states.

so if school is state 7 only schools with state 7 should show

only instead state 6 is showing the state 7 results....

where did I go wrong?

[Ruegen]

I have also tried Forms]![frmSchoolSearch]![cmbState]![tblSchools]![StateID]
with OR is null

same problem

Update - Wrong table in combo row source... ignore.