title: Hive from_unixtime for milliseconds
body: <p>We have a timestamp epoch column (BIGINT) stored in Hive.
  We want to get Date 'yyyy-MM-dd' for this epoch.
  Problem is my epoch is in milliseconds e.g. 1409535303522.
  So select timestamp, from_unixtime(timestamp,'yyyy-MM-dd') gives wrong results for date as it expects epoch in seconds.</p>
  
  <p>So i tried dividing it by 1000. But then it gets converted to Double and we can not apply function to it. Even CAST is not working when I try to Convert this double to Bigint.</p>