How to add custom fields in Apache Solr's search result?
If you have D7 and latest Solr search integration module then you can follow these steps:


Create a custom module with the following code (If your field is single value text then you should add "ts_" prefix to its name.)

function mymodule_apachesolr_query_alter($query) {
  $query-&gt;addParam('fl', 'ts_field_name');
}

Add the following function in the template.php file

function YOUR_THEME_preprocess_search_result(&amp;$variables) {
  $variables['ts_field_name'] = $variables['result']['fields']['ts_field_name'];
}

Display the field in search-result.tpl.php

&lt;?php if ($ts_field_name): ?&gt;
  &lt;?php print $ts_field_name; ?&gt;
&lt;?php endif; ?&gt;



This is a quick way that doesn't use any  theme function like theme_apachesolr_search_snippets() for search results snippets. 

You can find more information here:


http://archive.org/details/ApacheSolrSearchMastery_250
http://www.slideshare.net/AcquiaInc/apache-solr-search-mastery