title: Spark sql Unix timestamp returning wrong output
body: <p>The below query is returning <code>2017-02-23 00:45:00</code> instead of <code>12:45</code>.</p>
  
  <pre class="lang-scala prettyprint-override"><code>spark.sql("select from_unixtime(unix_timestamp(('2017-02-23 12:45:00')," +
            "'yyyy-MM-dd hh:mm:ss'))").show(false)
  </code></pre>
  
  <p>But the below query is returning expected output</p>
  
  <p><code>2017-02-23 13:45:00</code></p>
  
  <pre class="lang-scala prettyprint-override"><code>spark.sql("select from_unixtime(unix_timestamp(('2017-02-23 13:45:00')," +
            "'yyyy-MM-dd hh:mm:ss'))").show(false)
  </code></pre>
  
  <p>Can some one please help? </p>