题解 | #计算25岁以上和以下的用户数量#

select case when age < 25 or age is null then '25岁以下'
when age >=25 then '25岁及以上'
end as age_cut,count(*) as number FROM user_profile
GROUP BY age_cut

case when <condition> then <result>

when <condition> then <result> end