Hive之row_number() over分组排序

语法：ROW_NUMBER() OVER(PARTITION BY COLUMN ORDER BY COLUMN)

1.row_number() over()排序功能

分组排序：

已有表

E	E	E	9
C	E	A	5
B B E 8 D D C 6 E A B 6 C B D 10 C E C 4 E E D 1 D C C 8 D D E 3 B D A 9 A A C 4 C B B 3 D C A 2 C E D 10 A C C 3 D D C 1 A C D 5 E A D 1 B C A 5 C E B 8 B E B 3 

　　执行

select f1 as user_id,count(1) as times from test_data group by f1

A 16
B 10
C 10
D 12
E 12

现要求每个次数仅展示一名用户

select user_id,times
from(
select user_id,times,row_number() over(partition by times order by user_id) rn from( select f1 as user_id,count(1) as times from test_data group by f1) t1) t2 where rn<2 order by times;

B 10

D 12
A 16

来源：百度站长