Highest Salary in each department

Question

I have a table EmpDetails:

DeptID      EmpName   Salary
Engg        Sam       1000
Engg        Smith     2000
HR          Denis     1500
HR                  


        

Answer 1

select deptid, empname, salary from
(Select deptid, empname,salary,
rank() Over(Partition by deptid  order by salary desc)as rank from 
EmpDetails) emp 
where emp.rank = 1

First ranks each employee by salary in descending order having highest rank 1 and then selects only deptid, empname, salary. You can do this for all Nth member of the group.