title: multiple count conditions with single query
body: <p>I have a table like below -</p>
  
  <pre><code>Student ID | History | Maths | Geography
  1               A        B         B     
  2               C        C         E
  3               D        A         B
  4               E        D         A
  </code></pre>
  
  <p>How to find out how many students got A in history, B in maths and E in Geography with a single sql query ?</p>