diff --git a/lib/pg_searchable_regex.rb b/lib/pg_searchable_regex.rb
index 4387373..dc1b18d 100644
--- a/lib/pg_searchable_regex.rb
+++ b/lib/pg_searchable_regex.rb
@@ -36,7 +36,7 @@ module PgSearchable
       @ts_skip_cache_update = skip_callback
       @ts_wildcard = wildcard
       @ts_joins = joins
-      @default_field = (default_field.to_sym || fields.first)
+      @default_field = default_field.to_s.empty? ? fields.first : default_field.to_sym
       ts_add_scope
     end
 
diff --git a/lib/text_to_sql_query.rb b/lib/text_to_sql_query.rb
index d473f48..c464349 100644
--- a/lib/text_to_sql_query.rb
+++ b/lib/text_to_sql_query.rb
@@ -29,7 +29,7 @@ class TextToSqlQuery
     case first_key
     when :DEFAULT_COLUMN
       escaped_node_value = handle_special_chars node_value
-      ["#{@default_field.to_s} ILIKE ?", "%#{escaped_node_value}%"]
+      ["CAST(#{@default_field.to_s} AS TEXT) ILIKE ?", "%#{escaped_node_value}%"]
     when :OPERATOR_OR
       generate_expression_for_logical_operator(:OR, node_value)
     when :OPERATOR_AND
@@ -53,7 +53,7 @@ class TextToSqlQuery
       if mapping.nil?
         raise "Unknown field '#{first_key.to_s}'"
       else
-        ["#{mapping.to_s} ILIKE ?", "%#{escaped_node_value}%"]
+        ["CAST(#{mapping.to_s} AS TEXT) ILIKE ?", "%#{escaped_node_value}%"]
       end
     end
   end