Is there a way to compare the NULL value in the facets? Basically I want to

Is there a way to compare the NULL value in the facets?
Basically I want to add a facet in the record which will show only those records which has NULL completion date. The record field is of type datetime.
Now the operators available in the facets are "=", "<>" and "between". When I use = as operator, and null() as value, it will give me an error stating, "Cannot apply operator [EQUALS] to field [ProcessInstanceCompleted] when comparing to value [TypedValue[it=3,v=]]. (APNX-1-4203-015)"
Any pointers?...

OriginalPostID-112582

OriginalPostID-112582