SELECT every employee that has a higher salary than the AVERAGE of his department

Question

I have only 1 table named EMPLOYEE on my database with the 3 following collumns:

Employee_Name, Employee_Salary, Department_ID

Answer 1

please try with below query

Select * from employee a where Employee_Salary > (select avg(Employee_Salary) from 
employee b group by Department_ID having b.Department_ID = a.Department_ID)

or

Select * from employee a where Employee_Salary> (select avg(Employee_Salary) from 
employee b where b.Department_ID = a.Department_ID group by Department_ID)