title: Adding Percentage Column In Spark Dataframe using Scala
body: <p>I have below dataframe:</p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th>Name</th>
  <th>Dept</th>
  <th>Sal</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td>Ankit</td>
  <td>IT</td>
  <td>90</td>
  </tr>
  <tr>
  <td>Astha</td>
  <td>HR</td>
  <td>80</td>
  </tr>
  <tr>
  <td>Anku</td>
  <td>IT</td>
  <td>70</td>
  </tr>
  <tr>
  <td>Richa</td>
  <td>HR</td>
  <td>60</td>
  </tr>
  <tr>
  <td>Santa</td>
  <td>HR</td>
  <td>50</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p>I want to add two columns in this dataframe:</p>
  <p>1: salary percentage column
  2: department wise salary percentage column</p>