题解 | #截取出年龄#
截取出年龄
https://www.nowcoder.com/practice/b8d8a87fe1fc415c96f355dc62bdd12f
select
substring_index(substring_index(profile,',',-2),',',1) as age,
count(*) as number
from user_submit
group by age
截取字符串：
substring_index(substring_index(profile,',',-2),',',1) 取两次得到中间字符
每个年龄：group by
