Hi,
The following Postgres 7.1 query extracts aggregated data for an
arbitrary period within each year for sites in a table containing
30 years of temperature data.
topo=> \d longterm Table "longterm"Attribute | Type | Modifier
-----------+--------------+----------site | character(5) | not nullobs | date | not nulllo |
numeric(3,1)|hi | numeric(3,1) |
topo=> select site, extract(year from obs) as year, sum((hi+lo)/2-4) as
gdd4
topo=> from temperature
topo=> where extract(doy from obs) >= 1
topo=> and extract(doy from obs) <= 5
topo=> group by site, extract(year from obs);
site | year | gdd4
-------+------+--------01001 | 1973 | 51.701001 | 1974 | 39.501001 | 1975 | 67.9 . . . . .
.
My question is, how can this type of query be contructed to do
the same sort of thing for a period that straddles the calendar year
boundary?
--
Regards,
+----------------------+------------------------------------------+Ray Jackson email:
rmj@geography.otago.ac.nzComputingCoordinator phone: +64-3-479-8768Dept. Geography/Te Ihowhenua fax:
+64-3-479-8706OtagoUniversity postal: Box 56, DunedinTe Whare Wananga o Otago AOTEAROA/NEW
ZEALAND
+----------------------+------------------------------------------+
