my report output should be like this...

CEO
   |___GM
   |        |__HR Manager
   |        |            |__HR Executive
   |        |            |__HR Representative
   |        |__Purchase Manager
   |                     |__Purchase Executive
  

my table design is like this...

Desig_Code       Desig_Name                Reporting To
1                         CEO
2                         GM                                CEO
3                         HR Manager                   GM
4                         HR Executive                  HR Manager
5                         HR Representative          HR Manager
6                         Purchase Manager          GM
7                         Purchase Executive         Purchase Manager   


please help...
i tried with adding same table as alias, but not fitting to my needs, because n level of hierarchy is possible.

thanks in advance