stddev_y() | stddev_x()

Calculate the standard deviation from a two-dimensional statistical aggregate for the dimension specified

Since 1.3.0

Calculate the standard deviation from a two-dimensional statistical aggregate for the given dimension. For example, stddev_y() calculates the skewness for all the values of the y variable, independent of values of the x variable.

stddev_y(
  summary StatsSummary2D,
  [ method TEXT ]
) RETURNS DOUBLE PRECISION

stddev_x(summary
    StatsSummary2D,
    [ method TEXT ]
) RETURNS DOUBLE PRECISION

Arguments

Name	Type	Default	Required	Description
summary	StatsSummary2D	-	✔	The statistical aggregate produced by a stats_agg call
method	TEXT	sample	-	The method used for calculating the standard deviation. The two options are population and sample, which can be abbreviated to pop or samp

Returns

Column	Type	Description
stddev_y | stddev_x	DOUBLE PRECISION	The standard deviation of the values in the statistical aggregate

Samples

Calculate the standard deviation of a sample containing the integers from 0 to 100:

SELECT stddev_y(stats_agg(data, data))
  FROM generate_series(0, 100) data;

stddev_y
--------
29.3002