Question

确定拥有最多年任期的总统的姓名，政党和年数派对。我无法使用join关键字。

表总裁：

Name         | Party       | years_served|
-------------+-------------+-------------+
Roosevelt    | Democratic  | 12
Madison      | Demo-rep    | 8
Monroe       | Demo-rep    | 8
Adams        | Demo-rep    | 4

结果将是罗斯福，麦迪逊和梦露出现，亚当斯没有，因为他没有服务8年，这是演示代表的最大值。

Answer 1

您可以使用dense_rank()窗口功能：

with cte as (
    select
        *, dense_rank() over(partition by Party order by years_served desc) as rnk
    from Table1
)
select
    Name, Party, years_served
from cte
where rnk = 1

<强> sql fiddle demo

Answer 2

试试这个：

SELECT Name 
FROM President pr 
  INNER JOIN (SELECT Party, MAX(years_served) as YS FROM president GROUP BY Party) as MaxYS on MaxYS.Party=Pr.Party 
WHERE pr.years_served>=MaxYS.YS

希望就是你要找的。

查找行组POSTGRESQL的最大值

2 个答案: