MySQL in a Nutshell, 2nd Edition

Arithmetic Operators

The arithmetic operators in MySQL work only on numbers, not on strings. However, MySQL will convert a string into a number when in a numeric context if it can. If it can’t convert a particular string, it will return 0. Table B-1 lists the arithmetic operators allowed.

The minus sign may be used for subtracting numbers or for setting a number to a negative. The DIV operator converts values to integers and returns only integers. It doesn’t round fractions that would be returned, but rather truncates them.

Table B-1. Arithmetic operators

Operator	Use
+	Addition
–	Subtraction and negation
*	Multiplication
/	Division
DIV	Division of integers
%	Modulo division