• Specification

Example data:

(Just to become familiar with the characteristics)

select obstime, original from data where paramid=105 and obstime between '2008-06-23' and '2008-06-24' and stationid=17980;
       obstime       | original 
---------------------+----------
 2008-06-23 02:22:00 |      0.1
 2008-06-23 02:23:00 |      0.1
 2008-06-23 02:24:00 |      0.2
 2008-06-23 02:26:00 |      0.1
 2008-06-23 02:27:00 |      0.1
 2008-06-23 02:28:00 |      0.1
 2008-06-23 02:30:00 |      0.1
 2008-06-23 02:32:00 |      0.1
 2008-06-23 03:52:00 |      0.1
 2008-06-23 04:17:00 |      0.1
 2008-06-23 04:21:00 |      0.3
 2008-06-23 04:22:00 |      0.3
 2008-06-23 04:24:00 |      0.2
 2008-06-23 04:25:00 |      0.1
 2008-06-23 04:27:00 |      0.1
 2008-06-23 05:18:00 |      0.1
 2008-06-23 05:21:00 |      0.1
 2008-06-23 05:23:00 |      0.1
 2008-06-23 05:24:00 |      0.1
 2008-06-23 05:25:00 |      0.1
 2008-06-23 05:26:00 |      0.1
 2008-06-23 05:27:00 |      0.1
 2008-06-23 05:29:00 |      0.1
 2008-06-23 05:30:00 |      0.1
 2008-06-23 05:31:00 |      0.1
 2008-06-23 05:35:00 |      0.1
 2008-06-23 05:41:00 |      0.1
 2008-06-23 05:45:00 |      0.1
 2008-06-23 06:01:00 |      0.1
 2008-06-23 08:48:00 |      0.1
 2008-06-23 08:50:00 |      0.3
 2008-06-23 08:51:00 |      0.4
 2008-06-23 08:52:00 |      0.2
 2008-06-23 08:53:00 |      0.5
 2008-06-23 08:54:00 |      0.2
 2008-06-23 08:56:00 |      0.1
 2008-06-23 09:00:00 |      0.1
 2008-06-23 09:01:00 |      0.3
 2008-06-23 09:02:00 |      0.3
 2008-06-23 09:13:00 |      0.1
 2008-06-23 09:21:00 |      0.1
 2008-06-23 10:07:00 |      0.1
 2008-06-23 10:34:00 |      0.1
 2008-06-23 10:35:00 |      0.2
 2008-06-23 10:40:00 |      0.1
 2008-06-23 12:05:00 |      0.1
 2008-06-23 12:07:00 |      0.1
 2008-06-23 12:13:00 |      0.1