a tricky one

hi there,

something brainboggling :-)

three tables:
fac with:
id | integer | not null default
nextval('fac_id_seq'::text)

pre with:
id | integer | not null default nextval('pre_id_seq'::text)
fac_id | integer |
date | date |
production | float8 |

prd with:
id | integer | not null default nextval('prd_id_seq'::text)
date | date |
fac_id | integer |
prediction | float8 |

the last two have constraints as foreign keys "fac_id int4 references fac
(id)"

pre has only one row per month
prd has one value per day

if i do a

select

count(fac.id)
as fac_id,
sum(prd.production)
as prd_production,
sum(pre.prediction)
as pre_prediction

from
fac,
pre,
prd

where
date_part('year',timestamp(prd.date))=date_part('year',timestamp(pre.date))
and
date_part('month',timestamp(prd.date))=date_part('month',timestamp(pre.date))
and
pre.fac_id=fac.id
and
prd.fac_id=fac.id

group by
fac.id

what i acctually want is a result that shows the summed production of a year
and the summed prediction of a year at the same time

i got values of 365 for fac_id before i had the constraints :-), which was
perfectly well.

now it shows
372 (like 31x12) if i keep it as is
4392 (like 365x12) if i ommit the month-where-clause.

what's wrong

can anybody help, this goes over my know-how :-)
happy weekend

and thanks for the great help lately from the list

olaf

--
soli-con Engineering Zanger, Dipl.-Ing. (FH) Olaf Marc Zanger
Lorrainestrasse 23, 3013 Bern / Switzerland
fon:+41-31-332 9782, mob:+41-76-572 9782
mailto:olaf(dot)zanger(at)soli-con(dot)com, http://www.soli-con.com