题解 | 浙江大学用户题目回答情况

# 方法1：先在user_profile表里面找到浙江大学的device_id，然后在question_practice_detail里面找到对应device_id对应的数据
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

# 方法2：两张表联合进行查询（示例左外联结）
# select a.device_id,a.question_id,a.result
# from question_practice_detail a
# left join user_profile b
# on a.device_id = b.device_id
# where b.university = '浙江大学'

# 方法3：大神简洁版
# SELECT a.device_id,a.question_id,a.result
# from question_practice_detail a,user_profile b
# where university = '浙江大学'and a.device_id=b.device_id