title: How do I get unique values of a column in AWS Dynamo?
body: <p>Say, in AWS Dynamo, I have a table like this:</p>
  
  <pre><code>ID (HKey)   Date (RKey)   BoxName
  0           1/1/2014      Box-1
  1           2/1/2014      Box-1
  2           3/1/2014      Box-2
  3           4/1/2014      Box-3
  4           5/1/2014      Box-3
  5           5/1/2014      Box-1
  </code></pre>
  
  <p>I want to, in a single query, get the first row for each unique Box. There could be hundreds of boxes I need the first entry for at once, making individual requests inefficient.</p>
  
  <p>I can't seem to find anything in the API that would allow me to do this. Is it possible? How would I do this?</p>