diff --git a/src/AdvancedSearchQueryTerm.php b/src/AdvancedSearchQueryTerm.php
index 586fa5b..1e30eac 100644
--- a/src/AdvancedSearchQueryTerm.php
+++ b/src/AdvancedSearchQueryTerm.php
@@ -322,10 +322,11 @@ public function toSolrQuery(array $solr_field_mapping) {
       }
       // Fixed for https://github.com/digitalutsc/advanced_search/issues/4
       if ($this->field !== "all"){
-        $search_fields = "";
+        $search_fields = "(";
         foreach ($solr_field_mapping[$this->field] as $field) {
             $search_fields .= " $field:$value";
         }
+        $search_fields .= ")";
         return $search_fields;
       }
       return $value;