STDDEV_POP

This function returns the standard deviation of expr within a window or group of rows. Therefore, it has the following formula:

Syntax

stddev_pop::=

Usage Notes

  • With DISTINCT, the function considers duplicate values of expr only once. It considers all occurrences with ALL. If the function contains neither ALL nor DISTINCT, the default is ALL.
  • If a window or group has only one row, then the result of this function is 0.

Examples

Aggregate Function

SELECT 
    department, 
   STDDEV_POP(current_salary) STDDEV_POP
FROM employee_table GROUP BY department;
Result
DEPARTMENT STDDEV_POP
ACCOUNTS 9486.833
HR 12437.343

Analytic Function

SELECT 
    id, department, hire_date, current_salary, 
    STDDEV_POP(current_salary) OVER (PARTITION BY department ORDER BY hire_date) STDDEV_POP 
FROM employee_table ORDER BY department, hire_date;
Result
ID DEPARTMENT HIRE_DATE CURRENT_SALARY STDDEV_POP
2005 ACCOUNTS 2013-01-01 80000 0
2003 ACCOUNTS 2015-07-01 80000 0
2002 ACCOUNTS 2017-01-01 65000 6495.1905
2004 ACCOUNTS 2017-01-01 70000 6495.1905
2001 ACCOUNTS 2018-07-01 55000 9486.833
1003 HR 2014-01-01 90000 0
1002 HR 2016-01-01 70000 9428.0904
1004 HR 2016-01-01 70000 9428.0904
1001 HR 2018-01-01 55000 12437.343