title: Datediff function in hive
body: <p>Regarding <code>DateDiff</code> function </p>
  
  <pre><code>select datediff(current_date, '-2018-01-21');
  </code></pre>
  
  <p>what is <code>-</code> here as I know <code>datediff(enddata,startdate)</code> </p>
  
  <p>if we mention minus for <code>startdate</code> it getting number values <code>1474138</code> </p>
  
  <p>can please help to understand</p>