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POHow does one create a trigger which when a data set is entered for a new week, a calculation is performed on the previous week's data set in MySQL?
 

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  1. POHow does one create a trigger which when a data set is entered for a new week, a calculation is performed on the previous week's data set in MySQL?
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    <p>Lets say I have 2 tables:</p> <pre><code>DROP TABLE IF EXISTS `datasetCalculation`; DROP TABLE IF EXISTS `dataset`; CREATE TABLE IF NOT EXISTS `dataset`( `datasetID` INT NOT NULL AUTO_INCREMENT, `datasetWeekOf` DATE, #date indicates the beginning of a week `dataInsertedByID` INT NOT NULL, `datasetItem1` INT, `datasetItem2` INT, `datasetItem3` INT, PRIMARY KEY (`datasetID`, `datasetWeekOf`) )Engine = InnoDB; CREATE TABLE IF NOT EXISTS `datasetCalculation`( `datasetID` INT NOT NULL, `datasetWeekOf` DATE, `datasetItemSum` INT, PRIMARY KEY (`datasetID`, `datasetWeekOf`), CONSTRAINT `datasetID_FK` FOREIGN KEY (`datasetID`) REFERENCES `dataset` (`datasetID`) ON UPDATE CASCADE ON DELETE CASCADE, CONSTRAINT `datasetWeekOf_FK` FOREIGN KEY (`datasetID`) REFERENCES `dataset` (`datasetID`) ON UPDATE CASCADE ON DELETE CASCADE ) Engine = InnoDB; </code></pre> <p>What I'd like to do is when <code>dataset</code> is updated with the next week's information (it is updated once a week), automatically insert the relevant information into <code>datasetCalculation</code>. The equivalent would be to calculate in some language (let's say php) the sum of <code>datasetItem(1-3)</code>, then inserting that into <code>datasetCalculation</code>.<code>datasetItemSum</code> with the other relevant information. Instead I'd like this to be done automatically by the database.</p>
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    1. CODoes this thing bump it? Could really use some help here.
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      1. POHow does one create a trigger which when a data set is entered for a new week, a calculation is performed on the previous week's data set in MySQL?
      1. USNick
    2. COPlease explain the nature of calculations, specifically can they be made on a per source row basis or you need to operate with a set of source rows? Also provide sample data before and after calculations in tabular form.
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      1. POHow does one create a trigger which when a data set is entered for a new week, a calculation is performed on the previous week's data set in MySQL?
      1. USpeterm
 

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