题解 | #查看不同年龄段的用户明细#

select  device_id, gender,
    case 
    when age < 20 then '20岁以下'
    when age between 20 and 24 then '20-24岁'
    when age >= 25 then '25岁及以上'
    else '其他'
    end
    as age_cut
from user_profile

case

when...then...

end

或

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, gender