<< Click to Display Table of Contents >> ## STDDEV_SAMP |

Returns the statistical standard deviation of all values in number-expression, evaluated for each row remaining in the group and defined as the square root of the sample variance (VAR_SAMP).

STDDEV_SAMP ( [DISTINCT | ALL] number-expression )

where ALL includes (and DISTINCT excludes) duplicate values in the input set. ALL is the default. When the the input set has no non-null data, STDDEV_SAMP returns NULL.

STD_DEV is an alias of STDDEV_SAMP.

See also population standard deviation, STDDEV_POP, VAR_SAMP, and VAR_POP.