题解 | 分组计算练习题
分组计算练习题
https://www.nowcoder.com/practice/009d8067d2df47fea429afe2e7b9de45
select gender, university, count(gender) as user_num, round(avg(active_days_within_30), 1) as avg_active_day, round(avg(question_cnt), 1) as avg_question_cnt from user_profile group by gender,university order by gender asc, university asc
需要保留小数点后一位,所以必须加上round,count(gender)比count(*)更精准