How to Calculate Sum of Particular Column Based on Id in MySQL | Code Factory

My SQL Query :

select id, product_name as Product_Name, stock as Stock, sum(istock) as CF_Stock
from (
select *
from product_master t1,(
select as iid, t.stock as istock, t.product_name as product
from product_master t
) t2
where >= t2.iid
order by, t1.product_name, t2.product
) t3
where product_name = product
group by id, product_name
order by product_name, id;