title: How to specify group in RunningValue function in SQL Server Reporting Services?
body: <p>I have a data set with the following fields:</p>
  
  <pre><code>Serialnumber, Dateofpayment, Paymentamount, Sourcecode and Campaign.
  </code></pre>
  
  <p>My data has only two campaign types, BS12 and BS13.</p>
  
  <p>I'm trying to plot a running total of the payment amount by Campaign. In the chart I have the following expression for the Y value:</p>
  
  <pre><code>=RunningValue(Fields!PAYMENTAMOUNT.Value, SUM, "Campaign")
  </code></pre>
  
  <p>However, I keep getting the error:</p>
  
  <blockquote>
    <p>The Y expression for the chart 'Chart1' has a scope parameter that is not valid for RunningValue, RowNumber of Previous. The scope parameter must be set to a string constant that is equal to the name of a containing group within the Tablix 'Chart1'.</p>
  </blockquote>
  
  <p>I've looked up multiple sources and I feel like I am doing the right thing, Campaign is clearly a field in my tablix and I have entered it as a string. Why is the error occurring? - Can someone help me?</p>