title: how to find root parents in tree using neo4j?
body: <p>I have a tree, I would like to get all nodes at every level. The depth of tree could be anything.</p>
  
  <pre><code>node(1)&lt;-[PARENT]-node(2)&lt;-[PARENT]-node(3)&lt;-[PARENT]-node(4)
  node(1)&lt;-[PARENT]-node(5)&lt;-[PARENT]-node(6)
  node(2)&lt;-[PARENT]-node(7)
  node(5)&lt;-[PARENT]-node(8)
  node(2)&lt;-[PARENT]-node(9)
  </code></pre>
  
  <p>How to find root parent? (nodes who have no parents) please explain cypher query </p>