Percentage of Users Attended a Contest
Task: Find the percentage of users registered in each contest rounded to 2 decimals. Return sorted by percentage descending, then contest_id ascending.
Table: Users
+-------------+-------------+
| Column Name | Type |
+-------------+-------------+
| user_id | INT |
| user_name | varchar(20) |
+-------------+-------------+Table: Register
+-------------+------+
| Column Name | Type |
+-------------+------+
| contest_id | INT |
| user_id | INT |
+-------------+------+Input: Users table:
+---------+-----------+
| user_id | user_name |
+---------+-----------+
| 6 | Alice |
| 2 | Bob |
| 7 | Alex |
+---------+-----------+Register table:
+------------+---------+
| contest_id | user_id |
+------------+---------+
| 215 | 6 |
| 209 | 2 |
| 208 | 2 |
| 210 | 6 |
| 208 | 6 |
| 209 | 7 |
| 209 | 6 |
| 215 | 7 |
| 208 | 7 |
| 210 | 2 |
| 207 | 2 |
| 210 | 7 |
+------------+---------+Output:
+------------+------------+
| contest_id | percentage |
+------------+------------+
| 208 | 100 |
| 209 | 100 |
| 210 | 100 |
| 215 | 66.67 |
| 207 | 33.33 |
+------------+------------+