title: Show subtotal of a columns in the same Tablix in RDLC
body: <p>I am trying to generate subtotal of multiple columns in my Tablix, not in footer or header. I am using this expression:  </p>
  
  <pre><code>=SUM(ReportItems!ColumnName.Value)
  </code></pre>
  
  <p>This one works fine in footer.But for my work requirements I can't use the footer and must show the subtotal in the same tablix. While doing so it shows an error like this-  </p>
  
  <blockquote>
    <p>Aggregate functions can be used only on report items contained in page headers and footers</p>
  </blockquote>
  
  <p>Can anyone help me with this? </p>