title: How to fetch parent and child comment at single query?
body: <p>I have this table structure</p>
  
  <p>I want to build query through which i can fetch all the rows using tst_id (which is called parent comment) and this tst_id  should be matched with (if any) parent_tst_id  (these are called child comments) .BUT the condition is parent comment(parent_tst_id=0) and child comment (tst_id) should be fetch at the same time and in same query. </p>
  
  <pre><code>tst_id  mem_id  from_id      testimonial       added            parent_tst_id   
  3500    822     822     and KdevInd      1316613536         3497
  3499    329     329     Reply by me      1316613489         3497
  3498    821     821     a Fan comme      1316613307         3497
  3497    329     399     Profile COm      1316613243         0
  </code></pre>
  
  <p>please help,
  thanks</p>