Mysql或者Hive数据行变成列

对于mysql /  hive 再进行统计的时候假设须要行变成列，能够使用函数

CASE 字段a WHEN 值b THEN c [WHEN d THEN e]* [ELSE f] END 

当字段a=值b时,返回c（假设是字段的话则代表该字段的值，也能够是一个固定值 加单引號就能够）；当a=d时，返回e。否则返回f。

如：

数据表结构：(举例说明。id有反复的)

select id
,sum(CASE action when 'article' then count else 0 end) as article
,sum(CASE action when 'user_comment' then count else 0 end) as user_comment 
,sum(CASE action when 'profile' then count else 0 end) as `profile`
,sum(CASE action when 'user_follow' then count else 0 end) as user_follow 
,sum(CASE action when 'user_repost' then count else 0 end) as user_repost 
,sum(CASE action when 'user_timeline' then count else 0 end) as user_timeline 
from t_stat_user_action where stat_time='20150725' and id='1820485935'
group by id

结果为