title: find the difference between two columns in an ssrs matrix
body: <p>I have the following ssrs matrix that I am building :</p>
  
  <pre><code>Month(Column)
  Sales(Rows)               SalesData (Data)
  </code></pre>
  
  <p>My data looks something like this :</p>
  
  <pre><code>           Jan  Feb March 
  
    Sales     10    3   9
  </code></pre>
  
  <p>What I would like to do now is to find the difference between each of the rows to show 
    something like : </p>
  
  <pre><code>            Jan   Feb  March
  Sales        10    3    9
  #change           -7    6
  </code></pre>
  
  <p>In an ssrs table its a simple expression .</p>
  
  <p>I do not know how I need to do it in a matrix since the Months Columns are generated dynamically</p>
  
  <p>Please direct me..</p>
  
  <p>Just wanted to add this to clarify : </p>
  
  <p>This is how my matrix looks </p>
  
  <pre><code>                          Month(Column)
  Sales(Rows)               SalesData (Data)
  </code></pre>