调试易

执行这个SQL文,速度很慢,我想通过索引来提高一下速度,想请问一下,这个SQL中哪些字段都可以建立索引
select  
rnk_purchase_info.shop_id as shop_id ,
rnk_purchase_info.item_id as item_id ,
sum(rnk_purchase_info.units)  as quantity, 
count( distinct  rnk_purchase_info.order_num )  as order_num, 
sum(rnk_purchase_info.price*rnk_purchase_info.units) as volume,
sum(rnk_purchase_info.price*rnk_purchase_info.units)/sum(rnk_purchase_info.units)  as ppp,
count( distinct rnk_purchase_info.email ) as orderers , 
rnk_purchase_info.service_type as service_type   
from rnk_purchase_info 
inner join rnk_item_data 
inner join rnk_shop_mst 
inner join rnk_genreid_wk 
left join rnk_shop_blacklist on rnk_purchase_info.shop_id=rnk_shop_blacklist.shop_id 
and rnk_shop_blacklist.delflg=0
left join rnk_item_blacklist on rnk_purchase_info.shop_id=rnk_item_blacklist.shop_id 
and rnk_purchase_info.item_id=rnk_item_blacklist.item_id and rnk_item_blacklist.delflg=0
where
rnk_purchase_info.shop_id =rnk_item_data.shop_id and rnk_purchase_info.item_id =rnk_item_data.item_id
and rnk_purchase_info.shop_id=rnk_shop_mst.shop_id and rnk_shop_mst.open_flg=1 
and rnk_purchase_info.genre_id= rnk_genreid_wk.genre_id 
and rnk_shop_blacklist.shop_id is null 
and rnk_item_blacklist.item_id is null
and rnk_purchase_info.service_type=1
and rnk_purchase_info.mobile_flg=0
and rnk_purchase_info.prefecture=1
and rnk_item_data.inactive=0
and rnk_purchase_info.units > 0 
and rnk_purchase_info.reg_date>=date_sub( '20061022 00:00:00',interval 1 day )
and rnk_purchase_info.reg_date < '20061028 00:00:00'    
and rnk_purchase_info.gender_flg=0
and rnk_purchase_info.birth_year>=Year(now()) - 60 
and rnk_purchase_info.birth_year<=Year(now()) - 15and rnk_purchase_info.price>=5
and rnk_purchase_info.price<=100and rnk_purchase_info.purchase_id <= 10000000group by shop_id,item_id,service_type
order by ppp desc,quantity desc
limit 200;