SQL & PL/SQL

Hello,

I am using Oracle 11.2, I would like to use SQL to update one column based on values of other rows at the same table. Here are the details:

create table TB_test (myId number(4), crtTs date, updTs date);

insert into tb_test(1, to_date('20110101', 'yyyymmdd'), null);
insert into tb_test(1, to_date('20110201', 'yyyymmdd'), null);
insert into tb_test(1, to_date('20110301', 'yyyymmdd'), null);
insert into tb_test(2, to_date('20110901', 'yyyymmdd'), null);
insert into tb_test(2, to_date('20110902', 'yyyymmdd'), null);

After running the SQL, I would like have the following result:

1, 20110101, 20110201
1, 20110201, 20110301
1, 20110301, null
2, 20110901, 20110902
2, 20110902, null

Thanks for your suggestion.