VAR_SAMP

VAR_SAMP([ALL] expr) OVER over_clause

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