I orginally sent this email to the [novice] list but did not get any response.
I am look for help in developing a query that will return the nearest process record that waslogged at or after each
hourin a day (i.e. hourly snapshot).Below are typical sample data. Also, I've included a query used to return the
averageof theprocess value for each hour to give an example for the format that I am trying to achieve.Thanks for the
help.Regards,Richardselect* from process limit 10; tstamp | process---------------------+---------
2005-10-2521:10:41 | 3.56513 2005-10-25 21:10:42 | 3.56503 2005-10-25 21:10:43 | 3.56494 2005-10-25 21:10:44 | 3.56484
2005-10-2521:10:45 | 3.56475 2005-10-25 21:10:46 | 3.56465 2005-10-25 21:10:47 | 3.56455 2005-10-25 21:10:48 | 3.56446
2005-10-2521:10:49 | 3.56436 2005-10-25 21:10:50 | 3.56427(10 rows)select avg(process),
date_trunc('hour',tstamp)as date from process where date_trunc('day', tstamp) = '2005-10-26' group by
date_trunc('hour',tstamp) order by date_trunc('hour', tstamp); avg |
date------------------+---------------------9.79195118032606 | 2005-10-26 05:00:00 10.0249767947376 | 2005-10-26
06:00:008.88596018049452 | 2005-10-26 07:00:00 7.95090951088542 | 2005-10-26 08:00:00 8.10741349776586 | 2005-10-26
09:00:007.30079822791947 | 2005-10-26 10:00:00 7.10586501293712 | 2005-10-26 11:00:00 8.15196838166979 | 2005-10-26
12:00:008.26183129151662 | 2005-10-26 13:00:00 8.95141531440947 | 2005-10-26 14:00:00 10.562882253329 | 2005-10-26
15:00:0010.8634908244445 | 2005-10-26 16:00:00 11.4077104069976 | 2005-10-26 17:00:00 12.4702264580744 | 2005-10-26
18:00:0011.9155618293134 | 2005-10-26 19:00:00 11.5622152555012 | 2005-10-26 20:00:00 11.6527367563489 | 2005-10-26
21:00:0010.3170960432442 | 2005-10-26 22:00:00 9.56747980806563 | 2005-10-26 23:00:00(19 rows)
