update operator t set t.username = (select username from operator AS OF TIMESTAMP TO_TIMESTAMP('20150205 12:00:00','YYYYMMDD HH24:MI:SS') where id = t.id )
// 查询某个时间的数据库的数据
select *from table_name AS OF TIMESTAMP TO_TIMESTAMP('20150205 12:00:00','YYYYMMDD HH24:MI:SS')
update table_namet set t.username = (select username from operator AS OF TIMESTAMP TO_TIMESTAMP('20150205 12:00:00','YYYYMMDD HH24:MI:SS') where id = t.id )
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flashback table *表名* to timestamp to_timestamp('2016-06-26 08:30:00','yyyy-mm-dd hh24:mi:ss');
alter table *表名* enable row movement;
alter table *表名* disable row movement;