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Query performance

From: "Bill" <bill(at)math(dot)uchicago(dot)edu>
To: <pgsql-performance(at)postgresql(dot)org>
Subject: Query performance
Date: 2004-06-28 03:26:19
Message-ID: BILLSA1XvpFVjCRGryW00000002@bill.fefferman.org (view raw or flat)
Thread:
Lists: pgsql-performance
Actually, I have some queries that are slow, however I was wondering if you
could help me write a query that is rather simple, but I, as a true database
novice, can't seem to conjure.  So we have stocks, as I have previously
said, and I have a huge table which contains all of the opening and closing
prices of some stocks from each day.  What I like to do, in English, for
each stock in each day is find a ratio: abs(closing-opening)/opening.  Then
I would like to average all of the ratios of each day of each individual
stock together to find a final ratio for each stock, then I would like to
find the highest average, to find the best performing stock.  So what query
can I use, and (as is appropriate for this group), how can it be optimized
to run the fastest?

 

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Next:From: Tom LaneDate: 2004-06-28 03:29:46
Subject: Re: SQL stupid query plan... terrible performance !
Previous:From: JeffDate: 2004-06-28 02:48:16
Subject: Re: SQL stupid query plan... terrible performance !

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