题解 | #分组计算练习题#
分组计算练习题
https://www.nowcoder.com/practice/009d8067d2df47fea429afe2e7b9de45
# group by的作用是分组 分组对象通常是 gender 性别这种 还有就是university 学校 # 分组可以多分组 列名,列名 还有函数最好不用"列名" 这样的格式 select gender,university,count(gender) as user_num,avg(active_days_within_30) as avg_active_day,avg(question_cnt) as avg_question_cnt from user_profile group by gender,university
