题解 | #查看不同年龄段的用户明细#

select device_id, gender, '20岁以下' as age_cut
from user_profile
where age < 20
union all
select device_id, gender, '20-24岁' as age_cut
from user_profile
where age between 20 and 24
union all
select device_id, gender, '25岁及以上' as age_cut
from user_profile
where age >= 25
union all
select device_id, gender, '其他' as age_cut
from user_profile
where age IS NULL
order by device_id;