SQL in a Nutshell, 3rd Edition

Name

VAR_POP

Use VAR_POP to compute the population variance of a set of values.

ANSI SQL Standard Syntax

VAR_POP(numeric_expression)

MySQL and PostgreSQL

MySQL and PostgreSQL support the ANSI SQL syntax.

Oracle

Oracle supports the standard syntax. It also supports the following analytic syntax:

VAR_POP(numeric_expression) OVER (window_clause)

For an explanation of the window_clause, see the section later in this chapter titled “ANSI SQL Window Functions.”

SQL Server

Use the VARP function.

Example

The following example computes the population variance for the values 1, 2, and 3:

SELECT * FROM test;
         X
----------
         1
         2
         3

SELECT VAR_POP(x) FROM test;
VAR_POP(X)
----------
.666666667