(sale_id, year) is the primary key (combination of columns with unique values) of this table.
product_id is a foreign key (reference column) to Product table.
Each row of this table shows a sale on the product product_id in a certain year.

QUERY 1:

SELECT
    product_id,
    MIN(year) first_year,
    quantity,
    price
FROM 
    sales
GROUP BY
    product_id

QUERY 2:

select 
    product_id, 
    year as first_year, 
    quantity, 
    price
from 
    Sales
where
    (product_id, year) in (
                            select 
                                product_id, 
                                min(year) 
                            from 
                                Sales
                            group by 
                                product_id
                            )

This is from a problem in LeetCode, my solution is Query#1 (it did not work), however, Query#2 seems to work but I cannot understand what the difference between the two is