Calculating a new interim value and then sorting by the new value

Experts,

I have a table 'myTable' in a database with columns 'xxx' and 'yyy'. I would like to calculate a new column 'rating' based on some conditional statements and then sort the record set using the new column.

At the moment, I call the record set and store the values in PHP variables, then use the following PHP conditional statements to assign the rating:
<?php
/*
///////////////////////
// CALCULATE  RATING //
///////////////////////
*/

if(isset($xxx)&&isset($yyy)){
	if($xxx>10&&$yyy>100){$rating=5;}
	elseif($xxx>7&&$yyy>100){$rating=4;}
	elseif($xxx>10&&$yyy>70){$rating=4;}
	elseif($xxx>7&&$yyy>70){$rating=3;}
	elseif($xxx>3&&$yyy>70){$rating=3;}
	elseif($xxx>7&&$yyy>30){$rating=2;}
	elseif($xxx>3&&$yyy>70){$rating=2;}
	else{$rating=1;}
}else{
	echo "ERROR: Cant caclulate rating - arguments missing";
	$msg="ERROR: Cant caclulate rating - arguments missing";
	$rating=0;
}
?>

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The rating is then output to the screen.

This approach is ok, but it doesnt allow me to sort the information by this new rating value. Could someone suggest a method that i might use (preferably supply the SQL statement) to enable this operation to be processed by the MySQL statement?

Regards
Dean
LVL 12
Dean OBrienAsked:
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Brian CroweDatabase AdministratorCommented:
SELECT xxx, yyy,
      CASE
            WHEN xxx > 10 AND yyy > 1000 THEN 5
            WHEN xxx > 7 AND yyy > 100 THEN 4
            WHEN xxx > 10 AND yyy > 70 THEN 4
            WHEN xxx > 7 AND yyy > 70 THEN 3
            WHEN xxx > 3 AND yyy > 70 THEN 3
            WHEN xxx > 7 AND yyy > 30 THEN 2
            WHEN xxx > 3 AND yyy > 70 THEN 2
            ELSE 1
      END AS rating
FROM myTable

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DcpKingCommented:
You can create calculated fields in SQL Server, and then do things like order queries on the table by the value in a calculated field.

Here's a very simple table to try playing with:

CREATE TABLE [dbo].[__MyTest](
	[id] [int] NULL,
	[one] [int] NULL,
	[two] [int] NULL,
	[sum]  AS ([one]+[two]) PERSISTED,
	[product]  AS ([one]*[two]) PERSISTED
) ON [PRIMARY]

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Fill in the first two fields and then check out what you get - like this:
insert into __MyTest (id, one, two) select 1, 2, 4
select * from __MyTest

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hth

Mike
Ray PaseurCommented:
If you can't get the results in the SQL query, the theory and practice here may be helpful.
http://www.experts-exchange.com/articles/18319/Using-PHP-usort-to-Simplify-Complex-Data-Search.html
Dean OBrienAuthor Commented:
Thanks to everyone for their contributions.

Brian's solution did the trick perfectly.

Regards
Dean
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