select 
t1.style_id,
round(100*sum(sales)/(sum(inventory)-sum(sales)),2) pin_rate,
round(100*sum(gmv)/sum(tag_price*inventory),2) sellthrough_rate
from product_tb t1 
    join (select item_id,sum(sales_num) sales,sum(sales_price) gmv from sales_tb group by item_id)t2 on (t2.item_id = t1.item_id)
group by t1.style_id