解法一:left JOIN

select t1.device_id,question_id,result
from question_practice_detail t1
left JOIN user_profile t2
on t1.device_id = t2.device_id
where university = '浙江大学'

解法二:子查询

select 
device_id,
question_id,
result
from question_practice_detail
where device_id = (select device_id 
                   from user_profile 
                   where university = '浙江大学')