如何用collect_set等函数实现map结构的数据

1.数据准备

with temp_1 as (
    select 'zhangsan' as name , 'bj' as area,'math' as course , 88 as score

    union all 

    select 'lisi' as name , 'bj' as area,'math' as course , 99 as score

    union all 

    select 'wangwu' as name , 'sh' as area,'chinese' as course , 92 as score

    union all 

    select 'zhaoliu' as name , 'sh' as area,'chinese' as course , 78 as score

    union all 

    select 'tainqi' as name , 'bj' as area,'chinese' as course , 60 as score
)

select 
name
,area
,course
,score
from temp_1

结果如下：

name	area	course	score
tainqi	bj	chinese	60
wangwu	sh	chinese	92
zhaoliu	sh	chinese	78
lisi	bj	math	99
zhangsan	bj	math	88

2.集合表示

select 
course
,collect_set(score)
,collect_set(name)
from  temp_1
group by 
course

结果如下：

chinese	[92,60,78]	["zhaoliu","wangwu","tainqi"]
math	[88,99]	["zhangsan","lisi"]

3.字符串表示

select 
course
,concat_ws(',',collect_set(score))
,concat_ws(',',collect_set(name))
from  temp_1
group by 
course

结果如下：

math	99,88	lisi,zhangsan
chinese	92,60,78	wangwu,zhaoliu,tainqi

4.map形式表示

select 
course
,concat('{"',concat_ws('","',collect_set(concat(name,'":"',score))),'"}') indica_tr
,str_to_map(concat_ws(',',collect_set(concat(name,'=',score ))),',','=') indica_map
from  temp_1
group by 
course

结果如下：

math	{"lisi":"99","zhangsan":"88"}	{"lisi":"99","zhangsan":"88"}
chinese	{"tainqi":"60","zhaoliu":"78","wangwu":"92"}	{"tainqi":"60","wangwu":"92","zhaoliu":"78"}