title: Mysql, functions for tree-structure
body: <p>I have a tabel containing a column named parent which is able to store a parent ID.
  This makes it possible to create a tree-structure of my data.</p>
  
  <p>Are there any good helper-functions for travelling through such a tree-structure in MySQL?</p>
  
  <p>For example, if I have a row in my table and I want to be able to retreive all "parents" above it. So getting the it's parent's parent ID and so on...</p>