hive_case

case

1、例：

select u.uid,case 
when u.birthday>='1990' and u.birthday<='1999' then '90 后' 
when u.birthday>='1980' and u.birthday<='1989' then '80 后' 
when u.birthday>='1970' and u.birthday<='1979' then '70 后' 
when u.birthday>='1960' and u.birthday<='1969' then '60 后' 
when u.birthday>='1950' and u.birthday<='1959' then '50 后' 
else '其他' end as period from middle_bill_user u

运行

uid     period   
1        90 后
2        90 后
3        80 后
4        70 后
5        90 后
.....

再处理

select mbu.period, count(mbu.uid) as num from 
(select u.uid,case 
when u.birthday>='1990' and u.birthday<='1999' then '90 后' 
when u.birthday>='1980' and u.birthday<='1989' then '80 后' 
when u.birthday>='1970' and u.birthday<='1979' then '70 后' 
when u.birthday>='1960' and u.birthday<='1969' then '60 后' 
when u.birthday>='1950' and u.birthday<='1959' then '50 后' 
else '其他' end as period from middle_bill_user u) mbu group by mbu.period; '

结果

period   num
90后     121
80后      20
....