字符串转timestamp：
update tb_a t set t.upd_timestamp=to_timestamp('2012-12-12 12:12:12.0','yyyy-mm-dd hh24:mi:ss.ff') where t.id='1'
timestamp转字符串：
select to_char(t.upd_timestamp,'yyyy-mm-dd HH24:mi:ss:ff') from tb_a t
随便举个例子仅供参考
select * from Tfprecekweprcdtable where to_char(findfaulttime,'yyyy-mm-dd HH24')='2015-07-17 10';
