题解 | #分组计算练习题#
分组计算练习题
http://www.nowcoder.com/practice/009d8067d2df47fea429afe2e7b9de45
SELECT
gender,
university,
COUNT(device_id) 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;
计数 count 分组 group by 不跟在where后面 多个分组 group by gender， university 逗号隔开。
