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) age ,count(1) number FROM user_submit group by SUBSTRING_INDEX(SUBSTRING_INDEX(profile,',',-2),',',1)
考查SUBSTRING_INDEX的双重使用