title: What's the difference between Dataset.col() and functions.col() in Spark?
body: <p>Here's some statement: <a href="https://stackoverflow.com/a/45600938/4164722">https://stackoverflow.com/a/45600938/4164722</a></p>
  
  <blockquote>
    <p>Dataset.col returns resolved column while col returns unresolved column.</p>
  </blockquote>
  
  <p>Can someone provide more details? When should I use <code>Dataset.col()</code> and when <code>functions.col</code>?</p>
  
  <p>Thanks.</p>