您可以使用以下内容：
如果attendees_per_countries的列类型是字符串，则可以使用以下命令：

WITH sample_data AS (
    select 
        event_name, 
        str_to_map(
            regexp_replace(attendees_per_countries,'[{|}]',''),
            ',',
            ':'
        ) as attendees_per_countries 
    FROM
        raw_data
        
)
select 
    regexp_replace(cm.key,"[' ]","") as country,
    SUM(cm.value) as no_of_people
from sample_data
lateral view explode(attendees_per_countries) cm
GROUP BY regexp_replace(cm.key,"[' ]","")
ORDER BY no_of_people DESC

字符串
但是，如果attendees_per_countries的列类型已经是map，则可以使用以下命令

select 
    regexp_replace(cm.key,"[' ]","") as country,
    SUM(cm.value) as no_of_people
from sample_data
lateral view explode(attendees_per_countries) cm
GROUP BY regexp_replace(cm.key,"[' ]","")
ORDER BY no_of_people DESC

型
下面是完整的可再现示例

with raw_data AS (
    select 'a' as event_name, "{'US':5}" as attendees_per_countries
    UNION ALL 
    select 'b', "{'US':4, 'UK': 3, 'CA': 2}"
    UNION ALL 
    select 'c', "{'UK':2, 'CA': 1}"
),
sample_data AS (
    select 
        event_name, 
        str_to_map(
            regexp_replace(attendees_per_countries,'[{}]',''),
            ',',
            ':'
        ) as attendees_per_countries 
    FROM
        raw_data
        
)
select 
    regexp_replace(cm.key,"[' ]","") as country,
    SUM(cm.value) as no_of_people
from sample_data
lateral view explode(attendees_per_countries) cm
GROUP BY regexp_replace(cm.key,"[' ]","")
ORDER BY no_of_people DESC

型
告诉我这对你是否有效

在presto中，如果你有attendees_per_countries作为map，你可以使用map_values，然后将它们与array_sum/reduce相加（我需要稍后使用，因为Athena不支持前者）。如果没有-你可以将数据视为JSON并将其转换为MAP(VARCHAR, INTEGER)，然后使用上述函数：

WITH dataset(event_name, attendees_per_countries) AS (
   VALUES 
('a',   JSON '{"US":5}'),
('b',   JSON '{"US":4, "UK": 3, "CA": 2}'),
('c',   JSON '{"UK":2, "CA": 1}')
 ) 
 
SELECT event_name as country,
       reduce(
               map_values(cast(attendees_per_countries as MAP(VARCHAR, INTEGER))),
               0,
               (agg, curr) -> agg + curr,
               s -> s
           )      as number_of_people
FROM dataset
order by 2 desc

字符串
输出量：
| 国家|人数|
| --|--|
| B| 9 |
| 一| 5 |
| C| 3 |