select

    LEFT(rev_timestamp,4) as year,

    user_name,

    count(*) as undo_count

  from

    user,actor, revision_actor_temp,

    change_tag,

    page,

    revision

  where

    page_id = rev_page and

    page_namespace = 0 and

    user_id =actor_user and

    revactor_actor=actor_id and

    revactor_rev=rev_id and

    rev_id = ct_rev_id and

    ct_tag_id in (

       select

          ctd_id

       from

          change_tag_def

       where

          ctd_name = 'mw-undo' )

​

   Group by LEFT(rev_timestamp,4),user_name

   HAVING undo_count > 4

   ORDER by  year DESC,  undo_count DESC

   LIMIT 500;

​