The STDDEV_POP function returns the biased standard deviation (/n) of a set of numbers.
.-ALL------. >>-+-STDDEV_POP-+--(--+----------+--numeric-expression--)------>< '-STDDEV-----' '-DISTINCT-'
STDDEV_POP = SQRT(VAR_POP)
where SQRT(VAR_POP) is the square root of the variance.
If the argument is DECFLOAT(n), the result of the function is DECFLOAT(34). Otherwise, the data type of the result is double-precision floating point.
The function is applied to the set of values derived from the argument values by the elimination of null values. If DISTINCT is specified, duplicate values are eliminated.
The result can be null. If the function is applied to the empty set, the result is a null value. Otherwise, the result is the standard deviation of the values in the set.
The order in which the values are added is undefined, but every intermediate result must be within the range of the result data type.
Results involving DECFLOAT special
values: If the data type of the argument is decimal floating-point
and a special value of sNaN or -sNaN, or both +Infinity and -Infinity
are included in the aggregation, an error or warning is returned.
Otherwise, if +NaN or -NaN is found, the result is +NaN or -NaN. If
+Infinity or -Infinity is found, the result is +Infinity or -Infinity.
Syntax alternatives: STDEV_POP should be used for conformance to the SQL 2003 standard.
SELECT STDDEV_POP(SALARY) INTO :DEV FROM EMPLOYEE WHERE WORKDEPT = 'A00';Results in DEV being set to approximately 9742.43.