题解 | #浙江大学用户题目回答情况#
浙江大学用户题目回答情况
https://www.nowcoder.com/practice/55f3d94c3f4d47b69833b335867c06c1
方法一：嵌套子查询
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'
)
order by question_id
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'
)
order by question_id
方法二：连接查询
select
q.device_id,
q.question_id,
q.result
from
question_practice_detail q,
user_profile u
where
q.device_id = u.device_id
and u.university = '浙江大学'
order by
question_id
方法三：表连接查询
select
q.device_id,
q.question_id,
q.result
from
question_practice_detail q inner join
user_profile u on q.device_id = u.device_id
where
u.university = '浙江大学'
order by
question_id
q.device_id,
q.question_id,
q.result
from
question_practice_detail q inner join
user_profile u on q.device_id = u.device_id
where
u.university = '浙江大学'
order by
question_id
