title: Crystal Reports Running total formula doesnt work
body: <pre><code>WhileReadingRecords;
  numbervar Samples;
  if {product.sku}="card-sample" then
      Samples = Samples + {@num_qty};
  
  Samples;   
  </code></pre>
  
  <p>Above formula always returns Zero, I know @num_qty has values in it and in some rows it has NULL, if I tried to evaluate NULLS using below code, it gives me an error too</p>
  
  <pre><code>if (not (isnull{@num_qty})) then    
  </code></pre>
  
  <p>Any ideas ??? 
  Note: I'm trying this because, for my situation I cannot use CR built in Running totals </p>