题解 | #计算用户8月每天的练题数量#
计算用户8月每天的练题数量
http://www.nowcoder.com/practice/847373e2fe8d47b4a2c294bdb5bda8b6
select day(date) day,count(question_id) from question_practice_detail where month(date)=8 group by date ##我有点混乱了,关于having month(date)=8也可以得出结果 ##可以有人再讲下两个区别吗