s

SQL21是第一次遇到连接表的情况。

看看这张图，就知道我们应该用inner join来连接，只看t1.device_id = t2.device_id的情况

select t1.device_id, question_id, result 
from user_profile as t1 inner join question_practice_detail as t2
on t1.device_id = t2.device_id 
where t1.university='浙江大学';