Query objects with null value

Is there a way in to query objects that don't have object data tagged to them? I want to seperate the tagged objects from the untagged objects through a query. The way I'm doing it now, is that I first query all the tagged objects into a drawing. I then save that drawing as tagged objects. Next I have a blank drawing with SaveBack settings saved in it, so I attach original source drawing with all the objects in it (tagged and no tag) and query in the tagged drawing I just created, and then detach the orginal. I then used the save back options that we saved in the blank drawing and remove objects from the source drawing. This gives me one drawing with tagged objects and one drawing with no tagged objects.

There must be a better way, but I've tried everything and can't get it to work.

where object data value = < 0
where object data value = null
where object data value = ''
where object data value = ""

Nothing works,

Any ideas?

 

where object data value is null

 

Object Data is stored in a dictionary that is a child of
the object's extension dictionary. It's easy to determine
what the dictionary name is, and that's really all you need.

Just filter out objects that either have no extension
dictionary, or have no specific child dictionary within
their extension dictionary, with the determined name.