Advanced Search Pages

The Advanced Search Pages module extends the functionality of the Search API module (http://drupal.org/project/search_api) and its included Search Pages module. Once you have set up a search index, added fields to it, and created a search page, the Advanced Search Pages module lets you designate one or more of the indexed fields as "Advanced Search" fields to use on that page. These fields will appear in a fieldset, where users can choose specific values for each field. Furthermore, when performing an advanced search, the default keyword textfield can be left blank.

Thanks to the Search API Autocomplete module (http://drupal.org/project/search_api_autocomplete), any textfields you add to the advanced search will have autocomplete functionality, and all suggestions are retrieved directly from the search index. As of now, the Search API Autocomplete module only supports the Apache Solr backend.