hive分組隨機抽一定量數
阿新 • • 發佈：2019-02-11
要求根據員工的職級分類，然後每類職級隨機抽取2條資料，
建表：
create table temp.a
(id string,
name string,
age string,
rank string
)
ROW format delimited FIELDS TERMINATED BY ',' ;
load data local inpath 'a.txt' into table temp.a;
select * from temp.a;| id | name | age | rank |
| 1 | a | 10 | p1 |
| 2 | b | 34 | p1 |
| 3 | c | 23 | p2 |
| 4 | d | 33 | p2 |
| 5 | e | 23 | p2 |
| 6 | f | 67 | p3 |
| 7 | g | 34 | p3 |
| 8 | h | 12 | p4 |
| 9 | i | 54 | p5 |
SQL:
select id,
name,
age,
rank
from (
select id,
name,
age,
rank,
row_number()over(partition by rank order by rand()) as rn
from a
) t
where t.rn <=2結果1：
結果2：
注：如果order by rand(1),則每次排序相同，即出來的結果相同。