Query on self referncing table

hi CI Firiends
please can anyone tell me how can i query in self-refrence table?
i need to query the child that are referenced to parent by id

This is for CodeIgniter 3 but should be easy to modify for CodeIgniter 4.

How To Create Multi Level Nested Category Example In Codeigniter

Good luck.

What did you Try? What did you Get? What did you Expect?

Joined CodeIgniter Community 2009.  ( Skype: insitfx )