题解 | #每个用户的第一有效信息#
每个用户的第一有效信息
https://www.nowcoder.com/practice/4408f866778b44c5bcebf17c386d7d13
select
device_id,
(case
when answer_cnt is not null then concat('答题数:', answer_cnt)
when gpa is not null then concat('gpa:', gpa)
when age is not null then concat('年龄:', age)
else '暂无关键信息'
end) as key_info
from
user_profile
order by
device_id asc;
