title: Calculate percentage in SQL
body: <p>I've a table named <code>ExamResult</code> which has following columns</p>
  
  <pre><code>studentId, Subject, Standard, Marks
  </code></pre>
  
  <p>and i've following values in my table</p>
  
  <p>for studentId=1</p>
  
  <pre><code>1,maths,9,78
  1,english,9,80
  1,history,9,67
  1,geography,9,90
  </code></pre>
  
  <p>for studentId=2</p>
  
  <pre><code>2,maths,9,68
  2,english,9,83
  2,history,9,70
  2,geography,9,69
  </code></pre>
  
  <p>similar entries till studentId 30</p>
  
  <p>now I want to calculate the percentage of each student and want to select data from the table with the following columns</p>
  
  <pre><code>studentName(from student table),Standard,Percentage(with highest percentage on top)
  </code></pre>
  
  <p><strong>Eg:</strong> </p>
  
  <pre><code>Amit,9,78%
  Sam,9,77%
  </code></pre>
  
  <p>now the problem is how to calculate this percentage in SQL,</p>
  
  <pre><code>select stu.name,exam.standard,(what to do here) as Percentage 
  from Student stu 
  inner join ExamResult exam
  on stu.Id=exam.studentId;
  </code></pre>
  
  <p>Please help me</p>