如果在最后一个表中不需要空字符串和额外的逗号，那么可以按逗号拆分字符串，分解结果数组，然后收集集合，例如。

with table1 as (
  select row_number() over () as id, values
    from initial_table
),
table2 as (
  select id, value
    from table1
  lateral view explode(split(values, ',')) vals as value
),
table3 as (
  select id, collect_set(value) as values
    from table2
   group by id
)
select concat_ws(values, ',') as values
  from table3