On 2 June 2010 15:23, Michael Diener <m.diener@xxxxxxxxxx> wrote: > Hi, > > > > I’m new to the list and have the following situation happening "PostgreSQL > 8.4.1, compiled by Visual C++ build 1400, 32-bit" running windows XP sp3 > > > > I have an SQL problem that I thought was easy to do but gives me always the > wrong answer. > > > > 2 Tables with a column called “flaeche” “double precision”, in English > “area” and I want to sum up the values for flaeche in each table to give me > the total area for flaeche in each table. > > > > Correct answer comes with this sql > > select sum(flaeche)/10000 as "greens HA" from green; > > > > result: > > greenHA > > 1.25358085 > > > > Wrong Answer with this query > > select > > sum(green.flaeche)/10000 as "greens HA", > > sum (fairway.flaeche)/10000 as "fairway HA" > > from green, fairway; > > > > result: > > green HA fairway HA > > 48.8896531 508.94143659 > > > > Fairway correct answer is 14.96886578 HA > > Green correct answer is 1.25358085 HA > > > > What is going on ?? > > > > Cheers > > michael > > > > Michael Diener > > _________________________________________________________________ Could it be because you're effectively using a cartesian join? Can't you do them separately? Like: select sum(green.flaeche)/10000 as "greens HA" from green; select sum (fairway.flaeche)/10000 as "fairway HA" from fairway; Or if you must have both in the same result: select (select sum(green.flaeche)/10000 from green) as "greens HA", (select sum (fairway.flaeche)/10000 from fairway) as "fairway HA"; Regards Thom -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
