Re: Decimal Compare not working

[Rick James]

Computation tends to be done in DOUBLE. Constants tend to be DOUBLE. Numbers stored in DECIMAL(..,..) are not DOUBLE. In many cases, MySQL "does the right thing". But in some cases, it will be converting between DECIMAL and DOUBLE (either direction) and introduce a rounding error.

Your examples show $M... variables -- this is not SQL syntax. Please show us the actual SQL that is causing trouble if you want us to dig deeper.

Another thing to note... When doing a SELECT, SQL will return a string, not a binary number. The language you are working in may then turn that string into a DOUBLE in the language, thereby (possibly) adding a rounding error _outside_ of MySQL.