There are 2 tables:
EMP : EmpId, Ename, Sal, DeptId
DEPT : DeptId, Dname
Write a query to find out emp names and their department names. if any emp has null in Deptid the it shows
Write a query to find out those department names which
has no employee.
Write a query to find out those employees whose salary
is greater than their department?s average salary.