title: Sql Server 2008 Reporting Services: Using two dataset error
body: <p>Im building a report that's using two datasets. when I preview I find these types of errors...</p>
  
  <blockquote>
    <p>Error 19<br>  [rsFieldReferenceAmbiguous]<br> The Value expression for the text box ‘Textbox3’ refers directly to the field ‘PerZipCode’ without specifying a dataset aggregate.  When the report contains multiple datasets, field references outside of a data region must be contained within aggregate functions which specify a dataset scope.</p>
  </blockquote>
  
  <p>What aggregate function is needed and where is there an option to set this?</p>