VÄLJ ut varje anställd som har en högre lön än GENOMsnittet för hans avdelning

försök med nedanstående fråga

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)

eller

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)