Test for Null Output

Content Authoring
1

I would like to test the following relevance statement for null output. But using != null returns: the left operand of != must be singular.

(unique values of values of components whose (type of it="CN") of distinguished names (distinguished names of (groups of local computer of active directory;groups of local users of active directory)))
2

Here is what I have that seems to work:

concatenation of (unique values of values of components whose (type of it="CN") of distinguished names (distinguished names of (groups of local computer of active directory;groups of local users of active directory))) != ""
3

Try exists

exists (unique...)

4

That’ll do it too. exists is also useful when the results may not be strings.