Ah. Well that's a different question. You can, in fact, use aliases in ORDER BY (and GROUP BY):
SELECT ID, Title, MSRP, Price, round( ( (MSRP - Price) / MSRP) * 100) AS discount
FROM products
ORDER BY discount ASC
LIMIT 10
Now, regarding HAVING, I would imagine the HAVING clause would be faster, assuming you actually want the value of discount in the result of the SELECT. Otherwise, you're doing the calculation twice. No idea if that's true, though, so maybe someone else can give a definitive answer.
____________________________________________________________ Eamon Daly
----- Original Message ----- From: "Ed Lazor" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, October 11, 2004 4:51 PM
Subject: RE: Where clause question
Interesting. I thought you could sort by aliases. Thanks Shawn.
The easy answer was to just add the calculation to the where section as well. But which approach is faster - "having" or the calculation?
Ie.
select ID, Title, MSRP, Price, round( ( (MSRP - Price) / MSRP) * 100) as discount from products where round( ( (MSRP - Price) / MSRP) * 100) > 10
- OR -
select ... HAVING discount > 10
?
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