• 这道题主要是对每天进行分组，有关键字“每”
  • 日期函数year（）可以取出年份
  • month()可以取出月份
SELECT DAY(date) as day,COUNT(question_id) as question_cnt FROM question_practice_detail
WHERE MONTH(date) = 8 and YEAR(date) = 2021
GROUP BY day