STDDEV_SAMP

Returns the sample standard deviation (/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 standard deviation of the salaries for those employees in department A00.

   SELECT STDDEV_SAMP(SALARY)
     FROM EMPLOYEE
     WHERE WORKDEPT = 'A00';

Returns 10892.371183539422 when using the sample table.