SELECT to_timestamp(extract ('epoch' from Od_TimeStamp::timestamp)::int / (86400) * 86400)
as timeslice, sum(Od_Objects), sum(Od_Weight)
FROM overviewmonitoringdata
WHERE Ma_ID=3 AND Si_ID=0
AND Od_TimeStamp>='2010-04-01 00:00:00'
AND Od_TimeStamp<='2010-12-22 13:59:05'
GROUP BY timeslice
ORDER BY timeslice
Ergebnis:
timeslice sum sum_1
2010-03-31 02:00:00+02 40221 45228
Timestamps in der DB
01.04.2010 00:02:00
01.04.2010 00:03:00
01.04.2010 00:04:00
01.04.2010 00:05:00
01.04.2010 00:06:00
01.04.2010 00:07:00
01.04.2010 00:08:00
01.04.2010 00:09:00
