题解 | #月总刷题数和日均刷题数#
月总刷题数和日均刷题数
https://www.nowcoder.com/practice/f6b4770f453d4163acc419e3d19e6746
SELECT COALESCE(a.month, '2021汇总') AS submit_month,
COUNT(submit_time) AS month_q_cnt,
ROUND(
COUNT(submit_time)/MAX(month_days)
,3) AS avg_day_q_cnt
FROM(
SELECT DATE_FORMAT(submit_time,'%Y%m') AS month,
uid,
question_id,
submit_time,
DAYOFMONTH(LAST_DAY(submit_time)) AS month_days
FROM practice_record
WHERE YEAR(submit_time) = '2021'
) AS a
GROUP BY a.month
WITH ROLLUP
;
怪不得普通人连面试的机会都没有 笑了