题解 | #浙大不同难度题目的正确率#
浙大不同难度题目的正确率
https://www.nowcoder.com/practice/d8a4f7b1ded04948b5435a45f03ead8c
SELECT
qd.difficult_level AS difficult_level,
count( CASE WHEN result LIKE "%right" THEN "right" END ) / count( result ) AS correct_rate
FROM
user_profile up
LEFT JOIN question_practice_detail qpd ON up.device_id = qpd.device_id
LEFT JOIN question_detail qd ON qd.question_id = qpd.question_id
WHERE
up.university = "浙江大学"
GROUP BY
qd.difficult_level


