title: Use an Aggregate function in Sort Expression
body: <p>I have a report which uses a dataset returned from a stored procedure.  There are two key columns: <strong>Name</strong> and <strong>Value</strong></p>
  
  <p>I am using this dataset for two tablixes. The first is just a straightforward tablix displaying the data.</p>
  
  <p>The second groups the data based on a <strong>Name</strong> column. I need to order this data based on the Sum of <strong>Value</strong> column</p>
  
  <p>However I get the following error:</p>
  
  <blockquote>
    <p>[rsAggregateInDataRowSortExpression] A
    sort expression for the tablix
    'table1' includes an aggregate
    function.  Aggregate functions cannot
    be used in data row sort expressions.</p>
  </blockquote>
  
  <p>Is there another way I can show the data grouped by name and still order it by Sum(Value)?</p>