null problems

[Guest]

I have a form and a subform. A form with 3 combo boxes, and i set a
filter/query based on the values i choose from those combo boxes.The problem
is whenever there is a blank or let me say i didnt choose one box i dont have
output on the subform.
any help?thnks so much.

 

[Douglas J. Steele]

How are you referring to the combo boxes, and what do you want to happen if
nothing is chosen?

The usual approach is if nothing's chosen from a combo box, choose
everything from that field, rather than simply which rows have that field
matching what's selected. If that's what you want, presumably you've got

WHERE Field1 = Forms!MyForm!Combo1

in your query. Change that to

WHERE Field1 = Forms!MyForm!Combo1 OR Forms!MyForm!Combo1 IS NULL