Table: Users
+-------------+---------+ +| Column Name | Type | ++-------------+---------+ +| user_id | int | +| user_name | varchar | ++-------------+---------+ +user_id is the primary key (column with unique values) for this table. +Each row of this table contains the name and the id of a user. ++ +
+ +
Table: Register
+-------------+---------+ +| Column Name | Type | ++-------------+---------+ +| contest_id | int | +| user_id | int | ++-------------+---------+ +(contest_id, user_id) is the primary key (combination of columns with unique values) for this table. +Each row of this table contains the id of a user and the contest they registered into. ++ +
+ +
Write a solution to find the percentage of the users registered in each contest rounded to two decimals.
+ +Return the result table ordered by percentage in descending order. In case of a tie, order it by contest_id in ascending order.
The result format is in the following example.
+ ++
Example 1:
+ +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 | 100.0 | +| 209 | 100.0 | +| 210 | 100.0 | +| 215 | 66.67 | +| 207 | 33.33 | ++------------+------------+ +Explanation: +All the users registered in contests 208, 209, and 210. The percentage is 100% and we sort them in the answer table by contest_id in ascending order. +Alice and Alex registered in contest 215 and the percentage is ((2/3) * 100) = 66.67% +Bob registered in contest 207 and the percentage is ((1/3) * 100) = 33.33% ++