题解 | #计算25岁以上和以下的用户数量#
计算25岁以上和以下的用户数量
https://www.nowcoder.com/practice/30f9f470390a4a8a8dd3b8e1f8c7a9fa
select '25岁以下' as age_cut,count(device_id) as number
from user_profile
where age<25 or age is null
union all
select '25岁及以上' as age_cut,count(device_id) as number
from user_profile
where age>=25
from user_profile
where age<25 or age is null
union all
select '25岁及以上' as age_cut,count(device_id) as number
from user_profile
where age>=25
if和case更简单

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