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 empno 
from EMP e 
where salary=(select max(sal) 
              from EMP w 
              where  groupby w.deptno having e.deptno=w.deptno)

I hope it will work...