题解 | #截取出年龄#

# select substring_index(substring_index(profile,',',-2),',',1) as age,
# count(distinct device_id) as number
# from user_submit
# group by age; age升序

select substring_index(substring_index(profile,',',-2),',',1) as age,
count(device_id) as number
from user_submit
group by age;

不知道为何在device_id前加了distinct后，age的输出顺序会打乱。