题解 | #浙大不同难度题目的正确率#

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