Returns the biased standard deviation (/n) 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(SALARY) FROM EMPLOYEE WHERE WORKDEPT = 'A00';
Returns 9938.00 when using the sample table.