# Gini coefficient

The **gini** function calculates the Gini coefficient. The Gini
coefficient is a measure of unequal distribution. A return value of 0
signifies signals that all values are equal. The return values
approaches 1 if all values but one are zero.

The syntax of the function is

gini(x [,w])

x are the values for which the Gini coefficient shall be calculated.
Null values are ignored.

If the number of values is zero,
the function returns null.

w is the frequency with which the value x
occurs. If no frequency is provided, the frequency is assumed to be 1.

# Example

SELECT gini(salary) FROM persons;