oracle时间查询

　　select t.userid, count(t.id) num　　from sso_access_log t　　where 1 = 1　　and t.access_time >= to_date('2009-10-12 ', 'yyyy-MM-dd ')　　and t.access_time <= to_date('2010-11-08 ', 'yyyy-MM-dd ')　　group by t.userid　　order by num d