SQL> create table SCN_TEST (no number, name varchar2(20));

Table created.

SQL> insert into scn_test values (1,'a');

1 row created.

SQL> insert into scn_test values (2,'b');

1 row created.

SQL> insert into scn_test values (3,'c');

1 row created.

SQL> commit;

Commit complete.

SQL> select * from scn_test;

        NO NAME
---------- --------------------
         1 a
         2 b
         3 c

SQL> show parameter undo_retention

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
undo_retention                       integer     22719
SQL> select dbms_flashback.get_system_change_number from dual;

GET_SYSTEM_CHANGE_NUMBER
------------------------
                15893109

SQL> delete from scn_test where no = 2;

1 row deleted.

SQL> commit;

Commit complete.

SQL> select * from scn_test AS OF SCN 15893109 where no = 2;

        NO NAME
---------- --------------------
         2 b

SQL> insert into scn_test ( select * from scn_test AS OF SCN 15893109
  2                         where no = 2);

1 row created.

SQL> commit;

Commit complete.

SQL> select * from scn_test;

        NO NAME
---------- --------------------
         1 a
         3 c
         2 b

SQL>