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From: Bill <bill@math.uchicago.edu>
To: pgsql-performance@postgresql.org
Subject: Query performance
Date: Sun, 27 Jun 2004 22:26:19 -0500
Message-ID: <BILLSA1XvpFVjCRGryW00000002@bill.fefferman.org> (raw)

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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