爱吃菜叶的猫
爱吃菜叶的猫
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题解 | #平均播放进度大于60%的视频类别#
-- 计算各类视频的平均播放进度 SELECT tag, CONCAT(ROUND(AVG(IF(play_time >= duration, 100, play_time / duration * 100)), 2), '%') AS avg_play_progress FROM ...
Mysql
2022-05-01
0
174
题解 | #各个视频的平均完播率#
/* * 完播率:完整播放的次数 / 总播放次数 */ SELECT video_id, ROUND(COUNT(IF(play_time >= duration, video_id, NULL)) / COUNT(video_id), 3) AS avg_comp_play_ra...
Mysql
2022-05-01
0
159
题解 | #注册当天就完成了试卷的名单第三页#
SELECT uid, level, register_time, MAX(score) OVER(PARTITION BY uid) AS max_score FROM user_info JOIN exam_record USING(uid) J...
Mysql
2022-04-29
0
149
题解 | #注册时间最早的三个人#
SELECT uid, nick_name, register_time FROM user_info ORDER BY register_time LIMIT 3
Mysql
2022-04-29
0
162
题解 | #各用户等级的不同得分表现占比#
-- 统计不同用户等级的人完成的试卷数 -- 统计不同用户等级的人各得分等级试卷数 SELECT level, score_grade, ROUND( COUNT(uid) / total_cnt, 3 ) AS ratio FROM ( SELE...
Mysql
2022-04-29
0
210
题解 | #根据指定记录是否存在输出不同情况#
/* * 建立新表,记录用户试卷未完成数和未完成率 */ WITH incomplete_t AS ( SELECT uid, level, COUNT(IF(submit_time IS NULL, exam_id, NULL)) AS incomplete_cnt, ...
Mysql
2022-04-29
0
199
题解 | #筛选昵称规则和试卷规则的作答记录#
WITH valid_user AS (SELECT uid FROM user_info WHERE nick_name REGEXP '^牛客\\d+号$' OR nick_name REGEXP '^\\d+$'), valid_exam AS (SELECT exam_id FROM e...
Mysql
2022-04-29
0
153
题解 | #筛选限定昵称成就值活跃日期的用户#
第一次提交代码的时候直接用JOIN连接exam_record和practice_record,导致有一条用例没通过,后发现因为该用例中用户1005没有题目作答记录,故没有筛选进连接后的表中,改为left join后成功通过。 SELECT DISTINCT uid, nick_name, achie...
Mysql
2022-04-28
1
200
题解 | #0级用户高难度试卷的平均用时和平均得分#
SELECT uid, ROUND(AVG(score), 0) AS avg_score, ROUND(AVG(cost_time), 1) AS avg_time_took FROM ( SELECT uid, IF(submit_time IS NOT ...
Mysql
2022-04-28
0
161
题解 | #统计有未完成状态的试卷的未完成数和未完成率#
SELECT exam_id, incomplete_cnt, ROUND(incomplete_cnt / record_cnt, 3) AS incomplete_rate FROM ( SELECT exam_id, COUNT(start_time) AS ...
Mysql
2022-04-28
0
163
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