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POMySQL apply a value a field of each row based on the order of another field
 

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  1. POMySQL apply a value a field of each row based on the order of another field
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    <p>I have a table which I would like to apply a price rank for each record.</p> <p>1 for the highest, 2 for the next highest, 3 for the next highest.</p> <p>Currently I'm selecting each row and then updating each record individually like so:</p> <p>Usage: function get_list('table','order field','order direction') - returns associative array</p> <pre><code>foreach(get_list('ps2','price','DESC') as $p) { $ct++; $s = "UPDATE `ps2` SET `price_rank` = '".$ct."' WHERE `db_id` = '".$p[db_id]."' LIMIT 1"; mysql_query($s); } </code></pre> <p>As I have many records this is extremely slow, is there another way?</p> <p>Edit: Here's one way which is way faster but is there a better way?</p> <pre><code>ALTER TABLE `ps2` DROP `price_rank` ; ALTER TABLE `ps2` CHANGE `db_id` `db_id` INT( 11 ) NOT NULL ; ALTER TABLE `ps2` DROP PRIMARY KEY ; ALTER TABLE `ps2` ORDER BY `price_per_pax_after_tax` DESC; ALTER TABLE `ps2` ADD `price_rank` INT NOT NULL AUTO_INCREMENT PRIMARY KEY; ALTER TABLE `ps2` ORDER BY `db_id`; ALTER TABLE `ps2` CHANGE `price_rank` `price_rank` INT( 11 ) NOT NULL ; ALTER TABLE `ps2` DROP PRIMARY KEY ; ALTER TABLE `ps2` ADD PRIMARY KEY ( `db_id` ) ; ALTER TABLE `ps2` CHANGE `db_id` `db_id` INT( 11 ) NOT NULL AUTO_INCREMENT ; </code></pre>
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    1. USAndy Gee
    1. USAndy Gee
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    1. COYou are not giving enough information here, we need to see how do you calculate the price ranks in order to apply them to the table. At first glance, it looks like it should be possible to do with an update/case statement but again, without more details it's difficult to give you a concrete answer.
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      1. USIcarus
 

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