title: SSRS count rows grouping on data
body: <p>I have an existing SSRS report that shows some overall counts on the top of the report.  The report data looks like:</p>
  
  <pre><code>column1    column2
  A1         true
  -          true
  B5         false
  A1         true
  -          false
  C3         false
  </code></pre>
  
  <p>What I need is a distinct count of the items in column1, but including all the rows with the "-".  So the result for this example data should be 5, counting the "A1" rows as one.  The catch is that this needs to be done in an expression or some method on the report itself.  I cannot change the dataset queries.  </p>
  
  <p>I have tried:  =COUNTDISTINCT(Fields!column1.Value) but that counts the "-" rows as one.</p>
  
  <p>Is it possible to add another dataset and develop a query for that one that queries the existing dataset?  Not sure if that can be done.</p>