STDDEV [Aggregate]

Evaluates the statistical sample standard deviation for each member of the group. The return value is the same as the square root of VAR_SAMP:

STDDEV(expression) = SQRT(VAR_SAMP(expression))

Behavior Type

Immutable

Syntax

STDDEV ( expression )

Parameters

expression

Any NUMERIC data type or any non-numeric data type that can be implicitly converted to a numeric data type. STDDEV returns the same data type as expression.

Related Functions

  • Nonstandard function STDDEV is provided for compatibility with other databases. It is semantically identical to STDDEV_SAMP.
  • This aggregate function differs from analytic function STDDEV, which computes the statistical sample standard deviation of the current row with respect to the group of rows within a window.

  • When VAR_SAMP returns NULL, STDDEV returns NULL.

Examples

The following example returns the statistical sample standard deviation for each household ID from the customer_dimension table of the VMart example database:

=> SELECT STDDEV(household_id) FROM customer_dimension;
   STDDEV
-----------------
 8651.5084240071