Population Standard Deviation per Department

Return each department's population standard deviation of salary rounded to two decimals. Order by department_id.

Table schema

Employees(id INT PRIMARY KEY, department_id INT, salary INT)

Sample data

id | department_id | salary
1 | 1 | 10
2 | 1 | 20
3 | 1 | 30
4 | 2 | 50
5 | 2 | 50