title: Order parent child records by parent group and children
body: <p>I need sort query results by specific two related columns. My table is:</p>
  
  <pre><code>Row no | Col 1 | Col 2 | Col 3 | Col 4
      1  |   1   |  X    |  1    |  5
      2  |   2   |  Y    |  1    |  6
      3  |   5   |  Z    |  2    |  7
      4  |   6   |  T    |  2    |  0
      5  |   7   |  T    |  3    |  0
      6  |   6   |  W    |  2    |  0
  </code></pre>
  
  <p>The values in <code>Col 4</code> represents the child record linked to <code>Col 1</code>.  </p>
  
  <p>So for <code>Row no = 1</code> the next child record is row 3, where <code>Col 1</code> holds the value of <code>Col 4</code> from the first row.</p>
  
  <p>The next child row for row 3 is row 5, based on the link between <code>Col 1</code> and <code>Col 4</code>.</p>
  
  <p>And I'd like to return this results: </p>
  
  <pre><code>Row no | Col 1 | Col 2 | Col 3 | Col 4
      1  |   1   |  X    |  1    |  5
      3  |   5   |  Z    |  2    |  7
      5  |   7   |  T    |  3    |  0    
      2  |   2   |  Y    |  1    |  6
      4  |   6   |  T    |  2    |  0
      6  |   6   |  W    |  2    |  0 
  </code></pre>
  
  <p>So I want the ordering to show a Parent row, followed by it's child rows, before moving on to the next top level Parent row.</p>