title: how to calculate conditional sum in devexpress xtrareport
body: <p>Consider my following XtraReport</p>
  
  <p><img src="https://i.stack.imgur.com/XBZPZ.jpg" alt="enter image description here"></p>
  
  <p>It generates following output when previewed.</p>
  
  <p><img src="https://i.stack.imgur.com/BeJNo.jpg" alt="enter image description here"></p>
  
  <p>Notice the sum of Total marks in the report footer i.e 125.
  My Question is: How will I calculate the sum of the only fields where result is p. 
  Thus in this case sum of TotalMarks should be 75. </p>