USE provisioning;
SET autocommit=0;

SELECT `id` FROM `voip_preferences`
  WHERE attribute='announce_conn_type'
  INTO @pref_id;

DELETE FROM `voip_usr_preferences` WHERE attribute_id = @pref_id and value = "";
DELETE FROM `voip_dom_preferences` WHERE attribute_id = @pref_id and value = "";
DELETE FROM `voip_prof_preferences` WHERE attribute_id = @pref_id and value = "";

COMMIT;