title: How sum 'Tablix Column Values in a textbox' in SSRS
body: <p>In SSRS, I've tablix that is grouped by Products,as below:</p>
  
  <pre><code>Product | Billings
  
  ABC     | 15
  ABC     | 20
  XYZ     | 35
  </code></pre>
  
  <p>My business requirements are to get total billings in a separate textbox. I tried as below (Textbox2 is the tablix textbox for billings):</p>
  
  <pre><code>=Sum(ReportItems!Textbox2.value)
  </code></pre>
  
  <p>But it throws error:</p>
  
  <blockquote>
    <p>The Value Expression for the textbox 'Textbox3' refers to the report item 'Textbox2'. Report Items Expression can only refer to other report items within the same grouping scope or a containing grouping scope.` </p>
  </blockquote>
  
  <p>I need help on this to get it done. Thanks in Advance</p>