leaving list box null to choose all

[Schmidtty]

This may be an elementary question.
In my form.....I have several list boxes to choose: Region
and company size
and SIC code
and various other criteria.

This is put into a table which I then run a "filter" query off my main data table. I am fine if I fill in every box. Now, I want to leave a list box null and have it choose everything in that catergory.
Advice???

 

[llkhoutx]

Use the following record scource for your combobox:

Select Null, <All> from tbyourtable
Union
Select Id, AField from tbyourtable;

With the first column in the combobox hidden, <All> will appear in the combobox list, it ID value will be Nul, code appropriately.