title: reporting services - sum expression column in tablix
body: <p>I have a column in my tablix where I manually entered a long nested IF expression (its not in my dataset.)  I want to sum the whole column that contains my expression. Is there anyway to do this? </p>
  
  <p>Can I give the tablix column a name, and sum that? Or do I have to take my expressions and add them to my dataset? I rather not do this, because i have 8 datasets, and I would have to add 20 expressions to each one manually. </p>