Real vs. Floating Point vs. Money

Question

Why when I save a value of say 40.54 in SQL Server to a column of type Real does it return to me a value that is more like 40.53999878999 instead of 40.54? I\'ve seen this

Answer 1

In a nutshell, it's for pretty much the same reason that one-third cannot be exactly expressed in decimal. Have a look at David Goldberg's classic paper "What Every Computer Scientist Should Know About Floating-Point Arithmetic" for details.