表名（id, 逗号分隔的列名）
select id, 逗号分隔的列名from (select distinct id,
regexp_substr(逗号分隔的列名, '[^,]+', 1, level) 逗号分隔的列名
from 表名 where 逗号分隔的列名 is not null
connect by level <= regexp_count(逗号分隔的列名, ',') + 1
and id = prior id
and prior dbms_random.value is not null