How to Convert this sql query into laravel query builder

select t.product_id,t.on_hand,t.created_at from table t, (SELECT MAX(purchase_id) as pId FROM table Group by product_id) tg where t.purchase_id = tg.pId

from Newest questions tagged laravel-5 - Stack Overflow http://ift.tt/2juRDhw
via IFTTT