# Stddevw_samp Function

The **stddevw_samp** function returns the weighted standard deviation
of the sample for a set of values.

The syntax of the stddevw_samp function is

stddevw_samp(x[,w])

x are the values for which the standard deviation of the sample
shall be calculated.

Null values are ignored.

If the number of
values is zero, the function returns null.

w are the weights.
If no value is provided the weight is assumed to be 1.

# Example

SELECT country, stddevw_samp(price) FROM sales GROUP BY country;