根据列最大值获取记录

Question

我有带数据的汽车表

country | car      | price
---------------------
Germany | Mercedes | 30000
Germany | BMW      | 20000
Germany | Opel     | 15000
Japan   | Honda    | 20000
Japan   | Toyota   | 15000

我需要从表格中获取国家，汽车和价格，每个国家的价格最高

Germany Mercedes    30000
Japan   Honda       20000

Answer 1

尝试

    select cars.* FROM cars
    INNER JOIN (
        select country, max(price) AS maxprice from cars 
        GROUP BY country
    ) m
    ON cars.country = m.country AND cars.price = m.maxprice

Answer 2

使用ROW_NUMBER()

 SELECT *
 FROM ( SELECT *, 
               ROW_NUMBER() OVER (PARTITION BY country
                                  ORDER BY price DESC) as rn
        FROM cars ) as T
 WHERE T.rn = 1

如果允许平局，请改用RANK

 SELECT *
 FROM ( SELECT *, 
               RANK() OVER (PARTITION BY country
                            ORDER BY price DESC) as rn
        FROM cars ) as T
 WHERE T.rn = 1