title: referencing report fields in Birt
body: <p>My birt report has three tables, with different datasets/SQL sources, of course
  In the first, there is an aggregate field (SUM), tha is call "total_materias_primas"
  In the second, there is another aggregate, called "total_aditivos"
  And finally, in the third I need to aggregate(SUM) by one field, and then sum again my lastest "total_materias_primas" and "total_aditivos"
  I don't know how can be "total_materias_primas" and "total_aditivos" referenced in the third table/dataset</p>
  
  <p>Thanks</p>
  
  <pre><code>report["total_materias_primas"] /* no result */
  record["total_materias_primas"] /* no result */
  row["total_materias_primas"]    /* no result */
  </code></pre>
  
  <p>No code</p>