特殊的SQL

explain SELECT
	userinfo.avatar,
	userinfo.user_account,
	userinfo.user_name,
	userinfo.sex,
	additional.user_title AS juewei,
	IF(viprecord.end_time>now(),viprecord.vip_type,0) as vip,
	IF(backpack.goods_type=5,backpack.goods_id,0) as avatar_frame_url,
	IF(backpack.goods_type=2,backpack.goods_id,0) AS car,
	IF(backpack.goods_type=3,backpack.goods_id,0) AS chenghao,
	sum( rich.rich_num ) as totalsum
FROM
	quickchat_user_info AS userinfo
	INNER JOIN quickchat_user_additional AS additional ON  additional.user_account = userinfo.user_account
	LEFT JOIN 	(select user_account,goods_id,goods_type from (select * from quickchat_user_backpacker where is_use = "0" and end_time < now() ORDER BY end_time desc)  as t2 where t2.goods_type in ("2","3","5") GROUP BY t2.user_account,t2.goods_type) backpack ON userinfo.user_account = backpack.user_account 
	LEFT JOIN quickchat_rich_ranking AS rich ON   rich.user_account =userinfo.user_account
  LEFT JOIN quickchat_vip_record as viprecord on viprecord.user_account = userinfo.user_account
GROUP BY
	userinfo.user_account
order by totalsum desc
	limit 100