title: Apache Spark subtract days from timestamp column
body: <p>I am using Spark Dataset and having trouble subtracting days from a timestamp column.</p>
  
  <p>I would like to subtract days from Timestamp Column and get new Column with full datetime format. Example:</p>
  
  <pre><code>2017-09-22 13:17:39.900 - 10 ----&gt; 2017-09-12 13:17:39.900
  </code></pre>
  
  <p>With date_sub functions I am getting 2017-09-12 without 13:17:39.900.</p>