diff --git a/activerecord/lib/active_record/relation.rb b/activerecord/lib/active_record/relation.rb
index cb684c1109537b7d8a01db7bb6f4d11171284c84..948f33f24ee42d775c51d1a5b2be74e58a6e5ee8 100644
--- a/activerecord/lib/active_record/relation.rb
+++ b/activerecord/lib/active_record/relation.rb
@@ -249,6 +249,7 @@ def update(id, attributes)
     #
     #   Person.destroy_all("last_login < '2004-04-04'")
     #   Person.destroy_all(:status => "inactive")
+    #   Person.where(:age => 0..18).destroy_all
     def destroy_all(conditions = nil)
       if conditions
         where(conditions).destroy_all
@@ -298,6 +299,7 @@ def destroy(id)
     #
     #   Post.delete_all("person_id = 5 AND (category = 'Something' OR category = 'Else')")
     #   Post.delete_all(["person_id = ? AND (category = ? OR category = ?)", 5, 'Something', 'Else'])
+    #   Post.where(:person_id => 5).where(:category => ['Something', 'Else']).delete_all
     #
     # Both calls delete the affected posts all at once with a single DELETE statement.
     # If you need to destroy dependent associations or call your <tt>before_*</tt> or