题解 | #分组排序练习题#
分组排序练习题
https://www.nowcoder.com/practice/e00bbac732cb4b6bbc62a52b930cb15e
查看不同大学的用户平均发帖情况,并期望结果按照平均发帖情况进行升序排列
- 查看不同大学:
GROUP BY university
- 平均发帖情况:
AVG(question_cnt) AS avg_question_cnt
- 按照平均发帖情况进行升序排列:
ORDER BY avg_question_cnt
注意:
- order by最好写在group by后面(《SQL必知必会》)
- 读题可知,avg_question_cnt保留四位小数,将ROUND(a,b)跟AVG组合一下:
ROUND(AVG(question_cnt),4) AS avg_question_cnt
最后代码:
SELECT university,
ROUND(AVG(question_cnt),4) AS avg_question_cnt
FROM user_profile
GROUP BY university
ORDER BY avg_question_cnt
#sql#