title: how to do complex join on same column?
body: <p>I am trying to create a table using complex join among multiple tables..</p>
  
  <p><a href="https://i.stack.imgur.com/mqExZ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/mqExZ.png" alt="enter image description here"></a></p>
  
  <p>using <code>LEFT OUTER JOIN</code> will give following result</p>
  
  <p><a href="https://i.stack.imgur.com/pbuBa.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/pbuBa.png" alt="enter image description here"></a></p>
  
  <p>however, for all the rows where category is coming blank, i want to do an <code>SELF JOIN</code> on <code>sellerid</code> to get category filled</p>