STDDEV_SAMP

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>>-STDDEV_SAMP--(--+----------+--numeric-expression--)---------><
                   '-DISTINCT-'
 

The STDDEV_SAMP function returns the sample standard deviation (/n-1) of a set of numbers. The formula used to calculate the sample standard deviation is:

STDDEV_SAMP = SQRT(VAR_SAMP)

where SQRT(VAR_SAMP) is the square root of the sample variance.

numeric-expression
The argument values must be any built-in numeric data type.

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 or a set with only one row, 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.

Example