title: How to combine rows with the same ID into a list
body: <p>How can I make the below table like a list.</p>
  <pre><code>Id   Name
  1    Tim
  1    George
  2    Rachael
  3    Mark
  3    Blake
  </code></pre>
  <p>I want the result to be like this</p>
  <pre><code>Id    Name
  1     Tim,George
  2     Rachael
  3     Mark,Blake
  </code></pre>
  <p>Any ideas?</p>