------create table-----
create table emp_details(ID int, Name varchar(50),ManagerID int)
------insert data------
insert into emp_details values(101,'John',NULL)
insert into emp_details values(102,'Dan',101)
insert into emp_details values(103,'Amy',101)
insert into emp_details values(104,'Annie',101)
insert into emp_details values(105,'Watson',102)
insert into emp_details values(106,'Willson',102)
insert into emp_details values(107,'Tom',103)
insert into emp_details values(108,'Harry',103)
insert into emp_details values(109,'Keith',104)
insert into emp_details values(110,'Jones',104)
insert into emp_details values(111,'Fill',104)
insert into emp_details values(112,'Jack',105)