title: COLLECT_SET() in Hive, keep duplicates?
body: <p>Is there a way to keep the duplicates in a collected set in Hive, or simulate the sort of aggregate collection that Hive provides using some other method? I want to aggregate all of the items in a column that have the same key into an array, with duplicates.</p>
  
  <p>I.E.:</p>
  
  <pre><code>hash_id | num_of_cats
  =====================
  ad3jkfk            4
  ad3jkfk            4
  ad3jkfk            2
  fkjh43f            1
  fkjh43f            8
  fkjh43f            8
  rjkhd93            7
  rjkhd93            4
  rjkhd93            7
  </code></pre>
  
  <p>should return:</p>
  
  <pre><code>hash_agg | cats_aggregate
  ===========================
  ad3jkfk   Array&lt;int&gt;(4,4,2)
  fkjh43f   Array&lt;int&gt;(1,8,8)
  rjkhd93   Array&lt;int&gt;(7,4,7)
  </code></pre>