| 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) |