STDDEV_POP function

STDDEV_POP function STDDEV_POP is an aggregate function that evaluates the standard deviation of an expression over a population. STDDEV_POP aggregate function

See for more information about these functions.

STDDEV_POP is allowed only on expressions that evaluate to numeric data types.

Syntax STDDEV_POP ( expression )

The expression can contain multiple column references or expressions, but it cannot contain another aggregate or subquery. It must evaluate to a built-in numeric data type. If an expression evaluates to NULL, the aggregate skips that value.

The resulting data type is DOUBLE (it might overflow).

Formula

Standard deviation is calculated as follows:

sqrt( var_pop() ) Example -- find the standard deviation in flight time per aircraft SELECT AIRCRAFT, STDDEV_POP( flying_time ) FROM flights GROUP BY aircraft;