Returns the population 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_POP window function that performs a group, cumulative, or moving computation, see Window Aggregate Functions.
Standard Deviation
The standard deviation is the second moment of a population. For a population, it is a measure of dispersion from the mean of that population.
Do not use STDDEV_POP unless the data points you are processing are the complete population.
Computation
STANDARD DEVIATION OF A SAMPLE is valid only for numeric data.
Nulls are not included in the result computation.
When there are no non-null data points in the population, then STDDEV_POP returns NULL.
Division by zero results in NULL rather than an error.