Returns the sample standard deviation for the non-null data points in value_expression.
To invoke the time series version of this function, use the GROUP BY TIME clause. For more information, see Teradata Vantage™ - Time Series Tables and Operations, B035-1208.
For the STDDEV_SAMP window function that performs a group, cumulative, or moving computation, see Window Aggregate Functions.
The standard deviation is the second moment of a distribution. For a sample, it is a measure of dispersion from the mean of that sample. The computation is more conservative for the population standard deviation to minimize the effect of outliers on the computed value.
Division by zero results in NULL rather than an error.
When there are fewer than two non-null data points in the sample used for the computation, then STDDEV_SAMP returns NULL.