数据库 left join 优化问题

Question

sql为： （求怎么优化）
select ra.send_address_id as id, ra.providerid as providerid, ra.contact_username as contactusername, p.name as provincename, c.name as cityname, cs.name as areaname, ct.name as countryname, ra.country as country, ra.city as city, ra.area as area , ra.province as province, ra.street_address as streetaddress, ra.postal_code as postalcode, ra.telphone as telphone, ra.user_mobile as usermobile, ra.is_default as isdefault, ra.publish_time as publishtime, ra.publish_man as publishman, ra.update_time as updatetime, ra.update_man as updateman, ra.states as states from send_address ra left join province p on ra.province = p.id left join city c on ra.city = c.id left join county_seat cs on ra.area = cs.id left join country ct on ra.country = ct.id where ra.states = :1 and ra.providerid = :2 order by ra.is_default asc, ra.update_time desc

Answer 1

http://www.baidu.com/link?url=nyQP4VT-UUa1Dr78Qd5qJzjFfY7EVWnA1OBp63KfWMKsKtMaEB0ZixrHsMAx_j4uh_DY28psj60LQdiVGtIUDa&ie=utf-8&f=8&tn=34017009_11_pg&wd=%20left%20join%20%E4%BC%98%E5%8C%96