title: Need to subtract some hours from given timestamp in hive
body: <p>Input: unix_timestamp('01/15/2018 15:26:37', 'mm/dd/YYYY hh:mm:ss')</p>
  
  <p>Expected output is 4 hours delay from above utc input time i.e 01/15/2018 11:26:37</p>
  
  <p>I know that there is date_sub function in hive but it is only used to subtract days from the given timestamp. But I need to know if there is a way by which I can subtract hours or minutes or seconds.</p>
  
  <p>I have also tried something like below as EDT timezone is 4 hours behind UTC (but getting wrong output): </p>
  
  <pre><code>SELECT to_date(from_UTC_timestamp(unix_timestamp('01/15/2018 15:26:37', 'mm/dd/YYYY hh:mm:ss')*1000, 'EST6EDT')) as earliest_date; -- OUTPUT: 2017-12-31 (wrong) 
  </code></pre>
  
  <p>So can anyone help me out with this?</p>