title: get max value of each column group by student ID
body: <p>I have a table with columns like this</p>
  <pre><code>Std_id  Class Section
  14        8      2
  14        8      1
  14        9      1
  15        8      3
  15        8      2
  15        8      1
  
  Now I want student max class and max section by unique Student ID Like this
  
  Std_id  Class Section
  14        9      1
  15        8      3
  </code></pre>
  <p>I tried following queries with no success</p>
  <pre><code>SELECT std_id, class, section FROM `session` GROUP BY std_id ORDER BY std_id ASC,class DESC,section DESC
  </code></pre>
  <p>And</p>
  <pre><code>SELECT DISTINCT student_id, class_id, section_id FROM `student_session` ORDER BY student_id ASC,class_id DESC,section_id DESC
  </code></pre>