查数据库当前SCN号
col current_scn for 99999999999999999
select dbms_flashback.get_system_change_number current_scn from dual;
current_scn
------------------
881123135583
SQL> set num 50
SQL> select current_scn from v$database;
current_scn
---------------
881123135583
不畏将来,不念过往,如此,安好。--vast desert