SQL & PL/SQL

create table test11(tno number(8), tdate date, tval varchar2(55));
insert into test11 values(1,'15-JAN-2011', 'JSKD');
insert into test11 values(2,'31-JAN-2011', 'JSKD'); --------------
insert into test11 values(3,'14-MAY-2011', 'JSKD');
insert into test11 values(4,'31-MAY-2011', 'JSKD');-----------------
insert into test11 values(5,'15-JUN-2011', 'JSKD');
insert into test11 values(6,'30-JUN-2011', 'JSKD');--------------
insert into test11 values(7,'31-AUG-2011', 'JSKD');-----------
insert into test11 values(8,'20-NOV-2011', 'JSKD');-----------


i want output as

tno   tdate                    tval
2      31-JAN-2011         'JSKD'
4      31-MAY-2011        'JSKD'
6      30-JUN-2011        'JSKD'
7      31-AUG-2011        'JSKD'
8      20-NOV-2011         'JSKD'

i tried SELECT tno, MAX(TDATE) FROM TEST11 
group by to_char(tdate,'MMYYYY'),tno