title: Convert timestamp to interval in postgresql
body: <p>I am trying to convert a timestamp to interval &amp; expecting an out of hh:mm only.</p>
  
  <p>My code is like below</p>
  
  <pre><code>SELECT  to_timestamp('2020-01-10 08:00', 'YYYY-MM-DD hh24:mi')::timestamp without time zone 
          at time zone 'Asia/Calcutta' 
          at time zone 'Etc/UTC'
  </code></pre>
  
  <p>Actual purpose of the code is change the time zone into utc for a given date time value.</p>