title: How to get number or columns of a row from table with group by less columns?
body: <p>Hi this one is my Table</p>
  
  <pre><code>+-------------------------------------------------+
  |  name    |   sal    |  dept   |  age   | subdpt |
  +----------+----------+---------+--------+--------+
  |  sourav  |   1000   |  4      |  20    |  10    |
  |  ravi    |   1333   |  4      |  21    |  20    |
  |  dinesh  |   1444   |  5      |  22    |  30    |
  |  kumar   |   1000   |  5      |  23    |  30    |
  +-------------------------------------------------+
  </code></pre>
  
  <p>I want all columns with max sal group by dept and subdpt.
  please guide me. </p>