题解 | #浙江大学用户题目回答情况#

select device_id, question_id, result
from question_practice_detail
where device_id in
(select device_id from user_profile where university = "浙江大学");
在 () 中优先执行

SELECT u.device_id,q.question_id,q.result
from question_practice_detail q,user_profile u
where university = '浙江大学'and q.device_id=u.device_id
表名.属性可以在不同的表之间查询

SELECT u.device_id,q.question_id,q.result from question_practice_detail q
join user_profile u on q.device_id=u.device_id
where university="浙江大学"
联合查询