SQL>
SQL> SET ECHO ON
SQL> SET SERVEROUTPUT ON
SQL> DECLARE
2 a INTEGER;
3 b BOOLEAN;
4 n INTEGER; --this will be our null value.
5 BEGIN
6 a := 2;
7
8 IF (NOT (a = n)) IS NULL THEN
9 DBMS_OUTPUT.PUT_LINE('NOT NULL = NULL');
10 END IF;
11 END;
12 /
NOT NULL = NULL
PL/SQL procedure successfully completed.
SQL>