LeetCode（数据库）- 各赛事的用户注册率

题目链接：​​点击打开链接​​

题目大意：略。

解题思路：略。

AC 代码

SELECT contest_id, ROUND(COUNT(*) / (SELECT COUNT(*) FROM Users) * 100, 2) percentage
FROM Register
GROUP BY contest_id
ORDER BY percentage DESC, contest_id