HIve中case应用

示例数据：

ID 姓名  年龄  消费

id name age xf

101,zs,18,10045

102,ls,56,2222
103,ww,30,16666
104,zl,42,20000
105,tom,68,3000
106,jack,70,2000
107,amy,69,60000
108,lucy,12,200
109,frank,52,40000
111,mac,25,80000
112,ace,32,60000
113,tt,12,3000
114,hh,18,10000
115,haha,25,12000
116,hehe,19,1122
117,mm,20,56121
118,gg,36,222222
119,fuck,46,33333
121,hello,56,6558
122,goon,66,7000
123,soon,76,6666
124,good,86,5000
125,aa,96,100
126,kk,10,100

创建表格：

create table hehe(id int,name string ,age string,xf int) row format delimited fields terminated by ',' stored as textfile;

加载示例数据：

load data local inpath '/home/hadoop/hehe.txt' into table hehe;

1、统计各个年龄段人数
select aa.gg,count(*) from (select case when age<20 then '0-20岁' when 20<=age and age<40 then '20-40岁' when 40<=age and age<60 then '40-60岁'  else '60岁以上' end gg from hehe) aa  group by aa.gg;



查询结果：
0-20岁  6
20-40岁 6
40-60岁 5
60岁以上 7


2、统计各个年龄段消费情况的高低
select case when age<20 then (case when xf<1000 then '低消费' when xf>=1000 and xf<20000 then '适中' else '高消费'end) 
when 20<=age and age<40 then (case when xf<1000 then '低消费' when xf>=1000 and xf<20000 then '适中' else '高消费'end)
 when 40<=age and age<60 then (case when xf<1000 then '低消费' when xf>=1000 and xf<20000 then '适中' else '高消费'end) 
 else (case when xf<1000 then '低消费' when xf>=1000 and xf<20000 then '适中' else '高消费'end) end  
 from hehe;