题解 | #分群并计算群体人数#
分群并计算群体人数
https://www.nowcoder.com/practice/24319fd5c03e482c935783107114933d
这里我犯错的地方在于给case when加了括号，这里case when别名不能加括号，直接别名跟在后面就行
select
case
when age>50 then '50以上'
when age>=20 then '20-50'
when age<20 then '20以下'
else '未填写'
end age_group
,count(customer_id) as user_count
from customers_info
group by age_group
