|Oracle8i SQL Reference
Release 2 (8.1.6)
Functions, 116 of 121
For information on syntax and semantics, see "Analytic Functions".
VAR_POP returns the population variance of a set of numbers after discarding the nulls in this set. You can use it as both an aggregate and analytic function.
The expr is a number expression, and the function returns a value of type
NUMBER. If the function is applied to an empty set, it returns null. The function makes the following calculation:
The following example returns the population variance of the salaries in the EMP table:
The following example calculates the cumulative population and sample variances of the monthly sales in 1998: