I have been searching for a recent post which covered this but can't seem to find it. There are a few ways to do this, but basically you have to build the SQL string in VBA. Here is one that I found:
Code:
Dim SQL As String
SQL = "SELECT tblName.* From tblName WHERE (1=1)"
If Not IsNull(Me.combo1) Then
SQL = SQL & " And ([Field1] Like ""*" & Me.combo1 & "*"")" ' I am using like statements here, but that is because this is a search tool.
End If
If Not IsNull(Me.combo2) Then
SQL = SQL & " And ([Feild2] Like ""*" & Me.combo2 & "*"")"
End If
Docmd.RunSQL SQL
End Sub