there really isn't a workaround to this. what you can do though, (one option), is to hide another box on the form that you're opening the qry from, and on the action that opens the qry, give the hidden boxes the appropriate values if one of the regular inputs are null. for instance:
Code:
where myfield BETWEEN
[Forms]![Filters]![Text1sub]
AND
[Forms]![Filters]![Text2sub]
on the form, one could put behind the query event:
Code:
if isnull(me.text1) and isnull(me.text2) then
me.text1sub = 0
me.text2sub = 100000000000
elseif isnull(me.text1) then
me.text1sub = 0
elseif isnull(me.text2) then
me.text2sub = 100000000000
else
end if
docmd.openquery "QUERY"
the purpose of the really long number there is to give a ridiculous upper bound that no record could ever exceed.