title: Sql query with order by not working
body: <p>I want to join two tables namely staff and staff exam time tables. A staff can attend N number of Exams. My result should be staff id, staff name, end time of the last completed exam.</p>
  
  <p>My Table structure is below</p>
  
  <p>staff table</p>
  
  <pre><code>  staff_id  staff_full_name     staff_status
  
      500     Sakthi          active
  
      550     Siraj           active
  
      600     Shihab K H      active
  
      620     John David      active
  
      670     Javed Akthar        active
  </code></pre>
  
  <p>examtime table </p>
  
  <pre><code> examtime_id    examtime_staffid    examtime_endtime
  
      100     500         2014-10-10
  
      101     600         2016-05-01
  
      102     670         2016-06-10
  
      103     670         2014-04-01
  
      104     670         2016-06-13
  
      105     670         2016-06-11
  </code></pre>
  
  <p>SQL QUERY FOR THE RESULT SET IS BELOW</p>
  
  <pre><code>SELECT S.staff_id, S.staff_full_name, ET.examtime_endtime
  FROM staffs S LEFT JOIN examtime ET ON ET.examtime_staffid = S.staff_id
  WHERE 1 AND S.staff_status =  'active' GROUP BY S.staff_full_name ORDER BY S.staff_full_name ASC , ET.examtime_endtime DESC 
  </code></pre>
  
  <p>But I am getting the result set as below. It is fetching the first record of the exam time table irrespective of the exam end time. See below Result set ( Javed Akthar Latest exam date is 2016-06-13 but it is fetching 2016-06-10 ).</p>
  
  <pre><code>500 Sakthi      2014-10-10
  
  600 Shihab KH   2016-05-01
  
  670 Javed Akthar    2016-06-10
  </code></pre>