title: PHP SQL Based Tree view
body: <p>I want to have a php based tree view and user data is stored in SQL, 
  like the one shown in image. Please define how the SQL structure must be!
  <a href="https://i.stack.imgur.com/D3ewV.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/D3ewV.jpg" alt="enter image description here"></a></p>