Syntax
VAR_SAMP([ALL] expr) OVER over_clause
Purpose
You can call this function to return the sample variance of the expr expression.
If no matching row is found, it returns NULL.
Examples
obclient> CREATE TABLE EMPLOYEES (MANAGER_ID INT,LAST_NAME VARCHAR(50),HIREDATE VARCHAR(50),SALARY INT);
INSERT INTO EMPLOYEES VALUES(100, 'RAPHAELY', '2017-07-01', 1700);
INSERT INTO EMPLOYEES VALUES(100, 'DE HAAN', '2018-05-01',11000);
INSERT INTO EMPLOYEES VALUES(100, 'ERRAZURIZ', '2017-07-21', 1400);
INSERT INTO EMPLOYEES VALUES(100, 'HARTSTEIN', '2019-05-01',14000);
INSERT INTO EMPLOYEES VALUES(100, 'RAPHAELY', '2017-07-22', 1700);
INSERT INTO EMPLOYEES VALUES(100, 'WEISS', '2019-07-11',13500);
INSERT INTO EMPLOYEES VALUES(100, 'RUSSELL', '2019-10-05', 13000);
INSERT INTO EMPLOYEES VALUES(100, 'PARTNERS', '2018-12-01',14000);
INSERT INTO EMPLOYEES VALUES(200, 'ROSS', '2019-06-11',13500);
INSERT INTO EMPLOYEES VALUES(200, 'BELL', '2019-05-25', 13000);
INSERT INTO EMPLOYEES VALUES(200, 'PART', '2018-08-11',14000);
COMMIT;
obclient> SELECT LAST_NAME,SALARY,VAR_SAMP(SALARY) OVER(ORDER BY HIREDATE) AS DEVISION FROM EMPLOYEES WHERE MANAGER_ID = 100;
+-----------+--------+-----------------------------------------------+
LAST_NAME SALARY DEVISION
+-----------+--------+-----------------------------------------------+
RAPHAELY 1700 NULL
ERRAZURIZ 1400 45000
RAPHAELY 1700 30000
DE HAAN 11000 22110000
PARTNERS 14000 36783000
HARTSTEIN 14000 40200000
WEISS 13500 38991428.571428571428571428571428571428571428
RUSSELL 13000 36318392.857142857142857142857142857142857142
+-----------+--------+-----------------------------------------------+
8 rows in set (0.00 sec)