Leetcode SQL (#1068 – #1070)

select 
p.product_name, 
s.year, 
s.price
from Product p
    join Sales s 
        on p.product_id = s.product_id

select 
p.product_id, 
ifnull(sum(quantity),0) as total_quantity
from product p
    join sales s 
        on p.product_id = s.product_id
group by 1
order by 1

select 
product_id, 
year as first_year, 
quantity, 
price
from(
    select 
    product_id, 
    quantity, 
    price, 
    year, 
    rank() over(partition by product_id order by year) as seq
    from sales 
) s
where s.seq = 1