Purpose
This aggregate function can only be used in a query and requires a Group By clause in a field. The result of the StdDevP aggregate function is the population standard deviation of a numerical expression that is evaluated a number of times equal to its number of rows for each grouping obtained by the Group By clause.
Syntax
set variable := StdDevP(Expression)
Arguments
Expression | Any numerical expression |
Return value
For every group, the expression is evaluated for every row, then the population standard deviation is calculated based on all the obtained results.
Usually the StdDevP function is used to calculate the population standard deviation of the values of a numerical field with respect to a group.
Changed on: 17/12/2012 / From version: 8.5.3800