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 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(age) as number count中,NULL还是算不进去,所以count device_id count(device_id) as number from user_profile group by age_cut