name    |   job   | salary
-----------+---------+--------
 Joe       | develop |   2500
 Connor    | manager |   3500
 Callum    | sales   |   1400
 Kyle      | develop |   1200
 Jacob     | sales   |    950
 John      | manager |   1300

name    |   job   | salary | percent
-----------+---------+--------+---------
 Joe       | develop |   2500 |    67%
 Kyle      | develop |   1200 |    33%
 Connor    | manager |   3500 |    73%
 John      | manager |   1300 |    27%
 Callum    | sales   |   1400 |    59%
 Jacob     | sales   |    950 |    41%

SELECT name, job, salary, percent(sum(salary)*100/salary)
 OVER (PARTITION BY job) FROM emp;