.-ALL------. >>-+-STDDEV_POP-+--(--+----------+--numeric-expression--)------>< '-STDDEV-----' '-DISTINCT-'
The STDDEV_POP function returns the biased standard deviation (/n) of a set of numbers. The formula used to calculate the biased standard deviation is:
STDDEV_POP = SQRT(VAR_POP)
where SQRT(VAR_POP) is the square root of the variance.
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.
Syntax alternatives: STDEV_POP should be used for conformance to the SQL 1999 standard.
SELECT STDDEV_POP(SALARY) INTO :DEV FROM EMPLOYEE WHERE WORKDEPT = 'A00';Results in DEV being set to approximately 9742.43.
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