如何獲得Oracle中每個組的最大值？

Question

我發現了一些針對此問題的解決方案，但是，它們似乎不適用於Oracle。

我得到這個：

我想以目前大約只有年齡最大的人每隊的信息。所以，我的輸出應該是這樣的：

PERSON | TEAM | AGE 
Sam  | 1 | 23 
Michael | 2 | 21 

我怎麼能在Oracle中做到這一點？

Answer 1

一種方法是使用keep：

select team, max(age) as age, 
     max(person) keep (dense_rank first order by age desc) as person 
from t 
group by team; 

還有其他的方法，但以我的經驗，keep工作得很好。

Answer 2

下面是一個例子，而不keep但row_number()：

with t0 as 
(
    select person, team, age, 
    row_number() over(partition by team order by age desc) as rn 
    from t 
) 
select person, team, age 
from t0 
where rn = 1; 

Answer 3

select * from table 
where (team, age) in (select team, max(age) from table group by team)