SQL>
SQL>
SQL> declare
2 l_value1 varchar2(100);
3 l_value2 varchar2(100) := '';
4 l_value3 varchar2(100) := null;
5 l_value4 varchar2(100) default null;
6 begin
7 null;
8 end;
9 /
PL/SQL procedure successfully completed.
SQL>