VAR_POP

Purpose

This function returns the variance of expr within a window or group of rows. This equates to the following formula:

formula - var pop

Syntax

var_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

Copy 
SELECT 
    department, 
   VAR_POP(current_salary) VAR_POP
FROM employee_table GROUP BY department;
Result
DEPARTMENT VAR_POP
ACCOUNTS 90000000
HR 1.546875e+08

Analytic Function

Copy 
SELECT 
    id, department, hire_date, current_salary, 
    VAR_POP(current_salary) OVER (PARTITION BY department ORDER BY hire_date) VAR_POP 
FROM employee_table ORDER BY department, hire_date;
Result
ID DEPARTMENT HIRE_DATE CURRENT_SALARY VAR_POP
2005 ACCOUNTS 2013-01-01 80000 0
2003 ACCOUNTS 2015-07-01 80000 0
2002 ACCOUNTS 2017-01-01 65000 42187500
2004 ACCOUNTS 2017-01-01 70000 42187500
2001 ACCOUNTS 2018-07-01 55000 90000000
1003 HR 2014-01-01 90000 0
1002 HR 2016-01-01 70000 88888889
1004 HR 2016-01-01 70000 88888889
1001 HR 2018-01-01 55000 1.546875e+08