SELECT vs SET for creating variables

[Bill Dodson]

I am using version 4.0.12-nt on a Windows 2000 machine.

I have noticed some difference in the way SET and SELECT create 
variables.  The following statements do not work the way I would expect.

SELECT @neededStep := 10;
SELECT @startOfCenter := 7;
SELECT @returnData :=
IF(@neededStep <= @startOfCenter,
CONCAT(@neededStep, ' <= ', @startOfCenter),
CONCAT(@neededStep, ' > ', @startOfCenter)
);

In the above example @returnData ends up being '10 <= 7', but when 
@neededStep is less than 10 the expected results are found. (could this 
be because @neededStep is stored as text and not a number?)

In the next example @returnData ends up being '10 > 7', as expected.  
This seems to work for all values of @neededStep I have tested.

SET @neededStep := 10;
SET @startOfCenter := 7;
SELECT @returnData :=
IF(@neededStep <= @startOfCenter,
CONCAT(@neededStep, ' <= ', @startOfCenter),
CONCAT(@neededStep, ' > ', @startOfCenter)
);

It would seem that SET is a better way to create variables from constant 
values, but I would like to understand why.  Does anybody know what is 
happening here?

Thanks for your time!
bill

-- 
Bill Dodson
Parkline, Inc. http://www.parkline.com
phone: [phone] x149
fax: [phone]
email: bdodson@stripped


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