column.rb in pg_search-0.5

- old
+ new

@@ -24,10 +24,10 @@
         name = if foreign?
                  "#{@association.subselect_alias}.#{self.alias}"
                else
                  full_name
                end
-        "coalesce(#{name}, '')"
+        "coalesce(#{name}::text, '')"
       end
 
       def foreign?
         @association.present?
       end