On Mon, Jun 08, 2009 at 08:35:20AM +0200, Gerhard Wiesinger wrote: > Hello! > > I've the following data: > datetime | val1 | val2 > time1 | 4 | 40% > time2 | 7 | 30% > time3 | 12 | 20% > ... > > I'd like to sum up the following: > > (7-4)*30% + (12-7)*20% + ... This is best done in 8.4 using Windowing. Sadly, it's an 8.4-only feature, and dodgy hacks are the rule until you can use them. Cheers, David. > > datetime is ordered (and unique and has also an id). > > Rows are in the area of millions. > > How is it done best? > 1.) Self join with one row shift? > 2.) function? > > Any hint? > > Thnx. > > Ciao, > Gerhard > > -- > http://www.wiesinger.com/ > > > -- > Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-general -- David Fetter <david@xxxxxxxxxx> http://fetter.org/ Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter Skype: davidfetter XMPP: david.fetter@xxxxxxxxx Remember to vote! Consider donating to Postgres: http://www.postgresql.org/about/donate -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
