Returns the sample variance (/n-1) of a set of numbers. The argument values must be any built-in numeric data type and the sum must be within the range of the data type of the result.
Example:
Using the EMPLOYEE table, return the variance of the salaries for those employees in department A00.
SELECT VAR_SAMP(SALARY) FROM EMPLOYEE WHERE WORKDEPT = 'A00';
Returns 1.1864375E8 when using the sample table.