Re: Sum of multiplied deltas
От | Gerhard Wiesinger |
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Тема | Re: Sum of multiplied deltas |
Дата | |
Msg-id | alpine.LFD.2.00.0906082008090.10072@bbs.intern обсуждение исходный текст |
Ответ на | Re: Sum of multiplied deltas (David Fetter <david@fetter.org>) |
Ответы |
Re: Sum of multiplied deltas
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Список | pgsql-general |
Any hints for an 8.3 environment (currently)? Thnx. Ciao, Gerhard -- http://www.wiesinger.com/ On Mon, 8 Jun 2009, David Fetter wrote: > 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@postgresql.org) >> To make changes to your subscription: >> http://www.postgresql.org/mailpref/pgsql-general > > -- > David Fetter <david@fetter.org> http://fetter.org/ > Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter > Skype: davidfetter XMPP: david.fetter@gmail.com > > Remember to vote! > Consider donating to Postgres: http://www.postgresql.org/about/donate > > -- > Sent via pgsql-general mailing list (pgsql-general@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-general >
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