测试数据

hive> select * from col_lie limit 10;
OK
col_lie.user_id    col_lie.order_id
104399    1715131
104399    2105395
104399    1758844
104399    981085
104399    2444143
104399    1458638
104399    968412
104400    1609001
104400    2986088
104400    1795054

把相同user_id的order_id按照逗号转为一行

select user_id,
concat_ws(',',collect_list(order_id)) as order_value 
from col_lie
group by user_id
limit 10;

//结果(简写)
user_id    order_value
104399    1715131,2105395,1758844,981085,2444143

总结

使用函数：concat_ws(',',collect_set(column))  

说明：collect_list 不去重，collect_set 去重。 column的数据类型要求是string