oracle 时间按小时 分组统计
表：T
字段：begin_time,end_time,t_result
值：2009-08-11 00:30:00 , 2009-08-11 01:00:00, 10
2009-08-11 01:00:00 , 2009-08-11 01:30:00, 20
2009-08-11 01:30:00 , 2009-08-11 02:00:00, 30
2009-08-11 02:00:00 , 2009-08-11 02:30:00, 10
2009-08-11 02:30:00 , 2009-08-11 03:00:00, 10


我要显示

time,t_result
2009-08-11 01:00:00 10
2009-08-11 02:00:00 50
2009-08-11 03:00:00 20

就是按每小时统计一次结果；
oracle 求SQL或思路

------解决方案--------------------
数据固定的跳隔都是半个小时嘛?
------解决方案--------------------
select trunc(endtime-1/24/60/60,'HH')time,sum(t_result)t_result from T
group by trunc(endtime-1/24/60/60,'HH')
每小时自动统计可以通过job来实现