问题描述
|
我有一个事件日志表,记录每个行ID和DT_EVENT,即:
ID DT_EVENT
-------------------------
1 14-MAR-11 00:00:01
2 14-MAR-11 00:02:00
3 14-MAR-11 00:05:01
1 14-MAR-11 00:08:01
3 14-MAR-11 00:22:00
1 14-MAR-11 15:00:01
1 14-MAR-11 15:15:01
我需要对ID进行分组,并且需要从第一个ID事件开始间隔20分钟(例如20分钟)。就像是:
EV_GROUP ID DT_FirsT_EVENT DT_LAST_EVENT N_EVENTS
-----------------------------------------------------------------------
1 1 14-MAR-11 00:00:01 14-MAR-11 00:08:01 2
2 2 14-MAR-11 00:02:00 14-MAR-11 00:02:00 1
3 3 14-MAR-11 00:05:01 14-MAR-11 00:22:00 2
4 1 14-MAR-11 15:00:01 14-MAR-11 15:15:01 2
我不确定如何为该dt间隔设置group子句。有什么想法吗?
解决方法
SELECT id,diff,MIN(dt_event),MAX(dt_event)
FROM (
SELECT t.*,TRUNC((dt_event - FIRST_VALUE(dt_event) OVER (PARTITION BY id ORDER BY dt_event)) * 86400 / 1200) AS diff
FROM mytable t
)
GROUP BY
id,diff