Query Builder Date equal null

Hi,

I had following query in the On..Read method:
items = items.Where(items => items.Auslieferungsdatum == null);

80 entries are loading in the screen.

Now I tried the same in the query builder:

But now there are 0 entries loading?
How is it possible to do the query in the query builder? Thanks.

The easiest way will be to add raw filter expression: