·查看数据库版本
·SQL> select * from v$version;

BANNER
--------------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production
PL/SQL Release 11.2.0.1.0 - Production
CORE 11.2.0.1.0 Production
TNS for Linux: Version 11.2.0.1.0 - Production
NLSRTL Version 11.2.0.1.0 - Production

·查看当前scn，如下：
·SQL> select dbms_flashback.get_system_change_number from dual

GET_SYSTEM_CHANGE_NUMBER
------------------------
1155901
·SQL> select current_scn from v$database;

CURRENT_SCN
-----------
1155934

·采用scn_to_timestamp获取scn与时间的对应关系如下：
·SQL> select scn_to_timestamp(&scn) from dual;
Enter value for scn: 1155901
old 1: select scn_to_timestamp(&scn) from dual
new 1: select scn_to_timestamp(1155901) from dual

SCN_TO_TIMESTAMP(1155901)
---------------------------------------------------------------------------
05-APR-12 01.20.41.000000000 AM

SQL> /
Enter value for scn: 1155902
old 1: select scn_to_timestamp(&scn) from dual
new 1: select scn_to_timestamp(1155902) from dual

SCN_TO_TIMESTAMP(1155902)
---------------------------------------------------------------------------
05-APR-12 01.20.44.000000000 AM

SQL> select scn_to_timestamp(1155901) from dual;

SCN_TO_TIMESTAMP(2608762)
---------------------------------------------------------------------------
05-APR-12 01.20.41.000000000 AM


·scn_to_timestamp以及timestamp_to_scn的相互转化：
SQL> select timestamp_to_scn(to_timestamp('05-4月 -12 01.20.41.000000000 上午'))from dual;
select timestamp_to_scn(to_timestamp('05-4月 -12 01.20.41.000000000 上午')) from
dual
*
ERROR at line 1:
ORA-01843: not a valid month


·SQL> select timestamp_to_scn(to_timestamp('05-APR-12 01.20.41.000000000 AM')) from dual;

TIMESTAMP_TO_SCN(TO_TIMESTAMP('05-APR-12 01.20.41.000000000 AM'))
---------------------------------------------------------------
1155901

·SQL> select timestamp_to_scn(to_timestamp('05-04-12 01.20.41.000000000 AM')) from dual;

TIMESTAMP_TO_SCN(TO_TIMESTAMP('05-04-12 01.20.41.000000000 AM'))
---------------------------------------------------------------
1155901