title: Getting all parent rows in one SQL query
body: <p>I have a simple MySQL table thats contains a list of categories, level is determined by parent_id:</p>
  
  <pre><code>id  name    parent_id
  ---------------------------
  1   Home        0
  2   About       1
  3   Contact     1
  4   Legal       2
  5   Privacy     4
  6   Products    1
  7   Support     1
  </code></pre>
  
  <p>I'm attempting to make a breadcrumb trail. So i have the 'id' of the child, I want to get all available parents (iterating up the chain until we reach 0 "Home"). There could be any number or child rows going to an unlimited depth.</p>
  
  <p>Currently I am using an SQL call for each parent, this is messy. Is there a way in SQL to do this all on one query?</p>