1.FLASHBACK QUERY
闪回到15分钟前
SELECT * FROM tablename AS OF TIMESTAMP(SYSTIMESTAMP - INTERVAL '15' MINUTE ) WHERE 1=1;
这里可以使用DAY、SECOND、MONTH替换MINUTE ，例如：
SELECT * FROM tablename AS OF TIMESTAMP(SYSTIMESTAMP - INTERVAL '2' DAY) WHERE 1=1;
**闪回到某个时间点 **
SELECT * FROM tablename AS OF TIMESTAMP to_timestamp ('2014/05/20 08:20:00','yyyy/mm/dd hh24:mi:ss') WHERE 1=1;
闪回到两天前
select * from tablename as of timestamp (sysdate - 2) where.........
2.FLASHBACK DROP
flashback table tablename to before drop;
如果源表已经重建，可以使用rename to子句：
flashback table order to before drop rename to order_old_version;
3.FLASHBACK TABLE
1.首先要启用行迁移：
alter table tablenameenable row movement;
2.闪回表到15分钟前：
flashback table tablename to timestamp systimestamp - interval '15' minute;
3.闪回到某个时间点：
FLASHBACK TABLE order TO TIMESTAMP TO_TIMESTAMP('2007-09-12 01:15:25 PM','YYYY-MM-DD HH:MI:SS AM')