DECLARE

TYPE clientele IS TABLE OF VARCHAR2 (64);

group1 clientele := clientele ('Customer 1', 'Customer 2');

group2 clientele := clientele ('Customer 1', 'Customer 3', NULL);

group3 clientele := clientele ('Customer 3', NULL, 'Customer 1');

BEGIN

IF group1 = group2

THEN

DBMS_OUTPUT.put_line ('Group 1 = Group 2');

ELSIF group1 != group2

THEN

DBMS_OUTPUT.put_line ('Group 1 != Group 2');

END IF;

IF group2 != group3

THEN

DBMS_OUTPUT.put_line ('Group 2 != Group 3');

ELSIF group2 = group3

THEN

DBMS_OUTPUT.put_line ('Group 2 = Group 3');

END IF;

END;

/

/*======================================================================

| Supplement to the fifth edition of Oracle PL/SQL Programming by Steven

| Feuerstein with Bill Pribyl, Copyright (c) 1997-2009 O'Reilly Media, Inc.

| To submit corrections or find more code samples visit

| http://oreilly.com/catalog/9780596514464/

*/