title: finding duplicate field values in solr
body: <p>Using Solr 4.3</p>
  
  <p>I have a field "digest" in a solr index - and I would like to execute a query that will return me all the cases where there are duplicate values of digest. Can this be done? </p>
  
  <p>For the records that have duplicate values, I would like to return other values - such as "url" which may not be duplicated. </p>