Bill Dodson wrote:
> I am using version 4.0.12-nt on a Windows 2000 machine.
I have 4.1.11.
> 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?)
I get '10 > 7'.
> 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)
> );
This also gives me '10 > 7'.
> 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?
I expect it's a bug which has since been fixed (though I didn't check the bugs
db to be sure). You are using a very old version of mysql -- 4.0.12 was
released in March, 2003. The current version in the 4.0.x series is 4.0.25.
You can read the rather impressive list of bugs fixed since 4.0.12 in the
manual <http://dev.mysql.com/doc/mysql/en/news-4-0-x.html>. I'd suggest
upgrading.
> Thanks for your time!
> bill
Michael
