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(*) as number
# from user_profile
# where age<25 or age is null
# union
# select '25岁及以上' as age_cut,count(*) as number
# from user_profile
# where age>=25
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
添加计算列后使用group by函数
