title: SSRS - Calculate a Sum of notEmpty textbox
body: <p>I'm making a report with SSRS and I would liked to calculate the <code>notEmpty</code> textboxes.</p>
  
  <p>I have a tablix with about 15 columns and 3 of them are either empty or have a "X" as value that I have set in my Query.</p>
  
  <p>Those three columns are like that:</p>
  
  <p><img src="https://i.stack.imgur.com/1Cwd5.png" alt="tablix"></p>
  
  <p>Actually, it's based on time spent inside the store. Under 15 minutes, between 15 and 30 or over 30 min. And the ends, I would like to make a sum in the footer that calculate how many "X" there's in every sections/columns like this:</p>
  
  <p><img src="https://i.stack.imgur.com/q0WOD.png" alt="tablix with total"></p>
  
  <p>I know it's not well explained but I don't really know how to see it. I hope someone will be able to help me calculate this. </p>
  
  <p>Thanks</p>