Oracle null is null

NullNoGreater than/less than/equal to/not equal to any value (including null itself), and only:Null is null

SQL> set serveroutput on <br/> SQL> begin <br/> 2 if (2> null) <br/> 3 then <br/> 4 dbms_output.put_line ('>'); <br/> 5 elsif (2 <null) <br/> 6 then <br/> 7 dbms_output.put_line ('<'); <br/> 8 elsif (2 = NULL) <br/> 9 then <br/> 10 dbms_output.put_line ('='); <br/> 11 elsif (2! = NULL) <br/> 12 then <br/> 13 dbms_output.put_line ('! = '); <Br/> 14 else <br/> 15 dbms_output.put_line ('unknown! '); <Br/> 16 end if; <br/> 17 <br/> 18 if (null = NULL) <br/> 19 then <br/> 20 dbms_output.put_line ('null = null'); <br/> 21 elsif (null! = NULL) <br/> 22 then <br/> 23 dbms_output.put_line ('null! = Null'); <br/> 24 elsif (null is null) <br/> 25 then <br/> 26 dbms_output.put_line ('null is null '); <br/> 27 else <br/> 28 dbms_output.put_line ('unknown !! '); <Br/> 29 end if; <br/> 30 end; <br/> 31/</P> <p> unknown! <Br/> null is null </P> <p> PL/SQL procedure successfully completed </P> <p> SQL>