title: Pig - date string to long conversion
body: <p>I have some date values in the source text file, like column 3 below</p>
  
  <pre><code>123|text|2000-02-05 01:00:00-0500|true
  </code></pre>
  
  <p>how can I convert them to corresponding long value in Pig latin? Thanks.</p>
  
  <pre><code>a = load 'test.txt';
  b = &lt;what should be here&gt;(a);
  dump b; --output contains long value for column 3
  </code></pre>