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Performing On-Report Analysis with Web Intelligence 229

Using Web Intelligence functions

Overview

This chapter looks at the functions available in Web Intelligence. You often use functions

when creating Web Intelligence custom calculations.

This chapter covers the following topics:

•

what is a function?

• using functions

• function examples and descriptions

What is a function?

In mathematics, a function is a rule relating different values or sets of values. Functions

describe the relationships between variables and allow you to determine the value of one

variable given the value of another variable or variables. A function prototype (see below)

is a description of the relationship between input value(s) and output values and allows

you to derive a value (the output value) given zero or more existing values (the input value

or values). You input values to a function through its parameters and the function returns a

value related to the values of the parameters.

For example, the

Left() function describes the relationship between two input values (a

character string and an integer) and a character string output value. It outputs the first

[integer] characters of this character string as another character string. If the input string is

‘Hello’ and the input integer is 2, the output string is therefore ‘He’.

Note: Not all functions require input parameters.

Function prototypes

To use a function you need to know its name, how many input values it requires and the

data types of these input values. You also need to know the type of data that the function

outputs. For example, the Sum function takes a numerical object as input (for example a

measure showing sales revenue) and outputs numeric data (the sum of all the values of the

measure object).

This description of a function’s inputs and outputs it known as its prototype. The prototypes

of all Web Intelligence functions are listed in ”Functions available in Web Intelligence” on

page 233.