The standard Is Not Null predicate is supported to test whether or not an expression has a SQL NULL value (i.e., is undefined in a particular row). The generated SQL takes the form expression IS NOT NULL. When dragging an Is Not Null operator into a variable, the following tree element is created.
Columns and/or other expressions can be moved into the (empty) branches of the tree.
There are no special properties for the Is Not Null operator.