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Re: Running Total
Posted by: Peter Brawley
Date: April 15, 2007 04:32PM

Usually the turnaround time of a small aggregate query, eg "SELECT SUM(credit) - SUM(debit) AS balance FROM tbl WHERE id=$id", is a small fraction of the total turnaround time of sending a query to the server, retrieving the result, and repainting the client page, so the small performance gain you might enjoy from storing such balances is likely to be more than offset by the time it takes to update such aggregate values whenever one of their constituent items changes. So the usual rule, except in OLAP, is not to store what can be computed easily.

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April 15, 2007 04:04PM
Re: Running Total
April 15, 2007 04:32PM
April 15, 2007 08:33PM
April 15, 2007 09:08PM


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