On Feb 6, 2006, at 10:21 AM, Philippe Ferreira wrote:
Comparing two floating point numbers for equality seldom works
the way you want it to.
Without seeing the exact data you have it's hard to say for sure
(as there
may be some other issue with what you're doing) but I wouldn't expect
this to work with data from arbitrary sources.
Try
SELECT * FROM mytable WHERE myreal >= 10.49 AND myreal <= 10.51;
and see what result that gives.
This way, it works...
Then the problem you're seeing isn't database-related, it's just due to
the standard problem of misuse of floating-point numbers. You'll
need to go back and look at the queries you're using and see what
comparisons you really want your application to be doing.
<http://www.lahey.com/float.htm> (or maybe
<http://docs.sun.com/source/806-3568/ncg_goldberg.html>
depending on your maths background) is well worth a read.
Cheers,
Steve
