title: need a simple query in t-sql
body: <p>I have a query that I have simplified for our purpose. How do you achieve this result ?</p>
  
  <pre><code>ID OrigId
  ----------
  1   1
  2   1
  3   3
  4   4
  5   4
  6   6
  
  Result
  
  ID OrigId
  ----------
  1   1
  2   1
  4   4
  5   4
  </code></pre>