title: COUNT via multi-chain join
body: <p>I have this hierarchy in my database (from lowest to highest):</p>
  
  <p>User => Dept => Area => Company</p>
  
  <p>Now I need to make a table that shows all companies (some info about them taken directly from companies table) but the last column in the HTML table I want to be <strong>Number of users</strong>. I know I need to join the tables together and perhaps join table to itself, but how do I do this?</p>
  
  <p>Each of these tables have a column linking to its parent table (except Company ofc).</p>