VAR_SAMP()

Sample variance

Result type

DOUBLE PRECISION or NUMERIC depending on the type of expr

Syntax

VAR_SAMP ( <expr> )

Table 1. `VAR_SAMP` Function Parameters
Parameter	Description
expr	Numeric expression.It may contain a table column, a constant, a variable, an expression, a non-aggregate function or a UDF.Aggregate functions are not allowed as expressions.

The function VAR_POP returns the sample variance for a group or window.NULL values are skipped.

The function VAR_SAMP(<expr>) is equivalent to

(SUM(<expr> * <expr>) - SUM(<expr>) * SUM (<expr>) / COUNT (<expr>))
  / (COUNT(<expr>) - 1)

If the group or window is empty, contains only 1 row, or contains only NULL values, the result will be NULL.

select
  dept_no
  var_samp(salary)
from employee
group by dept_no