Numeric Functions

A list of the more useful numeric functions is shown in Table 8.4. There are many more in the manual.

Table 8.4. Numeric Functions

Function	Purpose
abs( n )	Returns the absolute value of n ”that is, the value without a sign in front of it.
ceiling( n )	Returns the value of n rounded up to the nearest integer.
floor( n )	Returns the value of n rounded down to the nearest integer.
mod( n,m ) and div	These two functions divide n by m . div returns the integral quotient , and mod() returns the integral remainder.
power( n,m )	Returns n to the power of m .
rand( n )	Returns a random number between 0 and 1. The parameter n is optional, but if supplied, it is used as a seed for the pseudorandom number generation. (Giving the same n to rand will produce the same pseudorandom number.)
round( n[,d] )	Returns n rounded to the nearest integer. If you supply d , n will be rounded to d decimal places.
sqrt( n )	Returns the square root of n .

Let's look at an example using mod() and div . One confusing thing about these functions is that whereas mod can be expressed as

 mod(9,2) 

or

 9 mod 2 

or even

 9 % 2 

the div function can be expressed only as

 9 div 2 

So, for example,

 div(9, 2) 

will not work and will give a syntax error.

Running mod and div in MySQL gives the following results:

 mysql> select 9 mod 2; +---------+  9 mod 2  +---------+        1  +---------+ 1 row in set (0.00 sec) mysql> select 9 div 2; +---------+  9 div 2  +---------+        4  +---------+ 1 row in set (0.00 sec)