STDDEV
STDDEV returns the sample standard deviation of expression, a set of numbers.
Syntax
STDDEV ( [DISTINCT | ALL ] expression) OVER (window_clause)
Remarks
• STDDEV differs from STDDEV_SAMP in that STDDEV returns zero when it has only 1 row of input data, whereas STDDEV_SAMP returns NULL.
• Without a window clause, STDDEV is a simple aggregate function.