variance aggregate function

Returns the sample variance calculated from values of a group.

Syntax

variance ( [ALL | DISTINCT] expr ) [FILTER ( WHERE cond ) ]

Arguments

  • expr: An expression that evaluates to a numeric.

  • cond: An optional boolean expression filtering the rows used for aggregation.

Returns

A DOUBLE.

If DISTINCT is specified the function operates only on a unique set of expr values.

This function is a synonym for var_samp aggregate function.

Examples

> SELECT variance(col) FROM VALUES (1), (2), (3), (3) AS tab(col);
  0.9166666666666666
> SELECT variance(DISTINCT col) FROM VALUES (1), (2), (3), (3) AS tab(col);
 1.0