Форум пользователей MySQL

SELECT *
FROM
     `businesses` b
     LEFT JOIN `businesses` b2 ON b2.`id` = b.`id_parent`
     LEFT JOIN `businesses` b3 ON b3.`id` = b2.`id_parent`
     LEFT JOIN `businesses` b4 ON b4.`id` = b3.`id_parent`
     
WHERE 189 = b.id
      OR 189 = b.`id_parent`
      OR 189 = b2.`id_parent`
      OR 189 = b3.`id_parent`
      OR 189 = b4.`id_parent`   
LIMIT 2900, 10

EXPLAIN:
id    select_type    table    type    possible_keys    key    key_len    ref    rows    Extra
1    SIMPLE    b    ALL    PRIMARY,FK_businesses_parent,id_parent,id                2761   
1    SIMPLE    b2    eq_ref    PRIMARY,id    PRIMARY    4    billing.b.id_parent    1   
1    SIMPLE    b3    eq_ref    PRIMARY,id    PRIMARY    4    billing.b2.id_parent    1   
1    SIMPLE    b4    eq_ref    PRIMARY,id    PRIMARY    4    billing.b3.id_parent    1    Using where

Почему ALL ?

CREATE TABLE `businesses` (
  `id` int(10) unsigned NOT NULL auto_increment,
  `id_parent` int(10) unsigned NOT NULL,
  `name` varchar(1600) NOT NULL,
  `path` tinytext,
  `document_type` tinyint(4) unsigned NOT NULL default '1',
  `document_sort` int(11) unsigned NOT NULL default '0',
  `document_gsort` varchar(255) character set utf8 collate utf8_bin NOT NULL,
  `document_level` int(11) unsigned NOT NULL default '0',
  `document_sub_folders` int(11) unsigned NOT NULL default '0',
  `document_sub_documents` int(11) unsigned NOT NULL default '0',
  `document_path` varchar(255) character set utf8 collate utf8_bin NOT NULL,
  `document_url` varchar(255) NOT NULL,
  `document_publish_time` int(10) unsigned NOT NULL,
  PRIMARY KEY  (`id`),
  KEY `FK_businesses_parent` (`id_parent`),
  KEY `id_parent` (`id_parent`,`id`),
  KEY `id` (`id`,`id_parent`),
  CONSTRAINT `FK_businesses_parent` FOREIGN KEY (`id_parent`) REFERENCES `businesses` (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;