【SQL】1070. 产品销售分析 III（窗口函数）

题目描述

leetcode题目：1070. 产品销售分析 III

方法一：窗口函数

select product_id, year as first_year, quantity, price
from (
    select *,
        dense_rank() over(partition by product_id order by year) as rk
    from Sales
) A
where A.rk = 1

方法二

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
)

记录自己的错误点

-- 	ERROR: 执行顺序是先group by product_id，会直接取相同product的第一行,此时order by year就失效了
-- select A.product_id, year as first_year, quantity, price
-- from(
--     select *
--     from Sales
--     group by product_id
--     order by year
-- ) A

修改第一行的测试用例