title: Sort Spark Dataframe with two columns in different order
body: <p>Let's say, I have a table like this:</p>
  
  <pre><code>A,B
  2,6
  1,2
  1,3
  1,5
  2,3
  </code></pre>
  
  <p>I want to sort it with ascending order for column <code>A</code> but within that I want to sort it in descending order of column <code>B</code>, like this:</p>
  
  <pre><code>A,B
  1,5
  1,3
  1,2
  2,6
  2,3
  </code></pre>
  
  <p>I have tried to use <code>orderBy("A", desc("B"))</code> but it gives an error.</p>
  
  <p>How should I write the query using dataframe in Spark 2.0?</p>