ORACLE BETWEEN AND查询时间段

--第一种方法 select * from info_stamp_user s where 
to_char(s.adddate,'yyyy-MM-dd HH24:mm:ss') 
between '2015-08-18 00:00:00'   and '2015-09-18 12:00:00'
--第二种方法 select * from tab where dtcol 
between to_date('2012-05-01 00:00:00','yyyy-mm-dd hh24:mi:ss') 
and to_date('2012-05-31 00:00:00','yyyy-mm-dd hh24:mi:ss')