SQL> DECLARE
2 empty_varchar2 VARCHAR2(10) := '';
3 empty_char CHAR(10) := '';
4 BEGIN
5 IF empty_varchar2 IS NULL THEN
6 DBMS_OUTPUT.PUT_LINE('empty_varchar2 is NULL');
7 END IF;
8
9 IF '' IS NULL THEN
10 DBMS_OUTPUT.PUT_LINE(''''' is NULL');
11 END IF;
12
13 IF empty_char IS NULL THEN
14 DBMS_OUTPUT.PUT_LINE('empty_char is NULL');
15 END IF;
16 END;
17 /
PL/SQL procedure successfully completed.
SQL>