题解 | #截取出年龄#
截取出年龄
https://www.nowcoder.com/practice/b8d8a87fe1fc415c96f355dc62bdd12f
select substring_index(substring_index(profile,',',3),',',-1) as age , # 3表示从正着数第三个 , 之前全拿出来 -1 表示倒数 第一个 , 之后全拿出来 count(device_id) as number from user_submit group by age