HiveQL--將多行數據聚合爲單行

Question

我正努力嘗試將多行數據寫入單個列。爲了讓這裏的例子是表我：

site  country users country _rank 
cnn.com  840  10000 1 
cnn.com  31   4000  3 
cnn.com  556  6000  2 
rt.com  840  200  3 
rt.com  33   6000  2 
rt.com  400  10000 1 

，我試圖得到結果後，用戶會爲前2個國家的＃，並把它在一個單行：

site  country_1 country_1_share  country_2  country_2_share 
cnn.com 840   10000    556   6000 
rt.com  400   10000    33   6000 

我試圖這樣做幾種不同的方式：

select site, country_1, country_1_share,country_2,country_2_share 
from (
    select site 
    ,max(CASE WHEN country_rank = 1 THEN country END) AS country_1 
    ,max(CASE WHEN country_rank = 1 THEN users END) as country_1_share 
    ,max(CASE WHEN country_rank = 2 THEN country END) AS country_2 
    ,max(CASE WHEN country_rank = 2 THEN users END) as country_2_share 
    from t1 
    group by site 
) 

也：

select a.site, a.country_1, b.country_1_share,c.country_2,d.country_2_share 
from (
    select site, country as country_1 
    from t1 
    where max(CASE WHEN country_rank = 1 THEN country END)) a 
JOIN (
    select site, users as country_1_share 
    from t1 
    where max(CASE WHEN country_rank = 1 THEN users END)) b on (a.site=b.site) 
JOIN (
    select site, country as country_2 
    from t1 
    where max(CASE WHEN country_rank = 2 THEN country END)) c on (a.site = c.site) 
JOIN (
    select site, users as country_2_share 
    from t1 
    where max(CASE WHEN country_rank = 2 THEN users END)) d on (a.site = c.site) 

任何有識之士將不勝感激！

Answer 1

能正常工作的蜂巢1.2.1：

drop table if exists t1; 

create table t1 
as 
select 'cnn.com' site, 840 country , 10000 users, 1 country_rank union all 
select 'cnn.com' site, 31 country , 4000 users, 3 country_rank union all 
select 'cnn.com' site, 556 country , 6000 users, 2 country_rank union all 
select 'rt.com' site, 840 country , 200 users, 3 country_rank union all 
select 'rt.com' site, 33 country , 6000 users, 2 country_rank union all 
select 'rt.com' site, 400 country , 10000 users, 1 country_rank; 

select site, country_1, country_1_share,country_2,country_2_share 
from (
    select site 
    ,max(CASE WHEN country_rank = 1 THEN country END) AS country_1 
    ,max(CASE WHEN country_rank = 1 THEN users END) as country_1_share 
    ,max(CASE WHEN country_rank = 2 THEN country END) AS country_2 
    ,max(CASE WHEN country_rank = 2 THEN users END) as country_2_share 
    from t1 
    group by site 
)s; 



OK 
site country_1  country_1_share country_2  country_2_share 
cnn.com 840  10000 556  6000 
rt.com 400  10000 33  6000