title: Taking care of daylight saving time when converting timezone
body: <p>I have a Redshift data table where all time values are stored in CST and I convert the time values to the respective timezone based on the zip code (location). </p>
  
  <p>While I do that, I understand that all time values are in Standard time and hence my function usage is </p>
  
  <pre><code>CASE WHEN **** convert_timezone('CST', 'EST', time_column)  
       WHEN **** convert_timezone('CST', 'MST', time_column)
  ....
  END
  </code></pre>
  
  <p>This may not be applicable once we enter into Daylight Savings time. <strong>How can I take care of this such that I do not modify the SQL query again in 2018 March and in future?</strong> </p>