怎么查询锁的历史记录，就想查询今天有多少表被锁过，然后操作锁的原因?

查询v$active_session_history
类似这种：
select a.session_id,

   a.BLOCKING_SESSION,
   a.sql_Id,
   to_char(sample_time, 'yyyy-mm-dd hh24:mi:ss'),
   a.time_waited

from v$active_session_history a
where a.EVENT = 'enq: TX - row lock contention'
and to_char(sample_time, 'yyyy-mm-dd hh24:mi:ss') between

   '2018-01-04 10:00:00' and '2018-01-04 11:00:00'

and a.BLOCKING_SESSION_STATUS = 'VALID'
ORDER BY to_char(sample_time, 'yyyy-mm-dd hh24:mi:ss') DESC