# 1633. Percentage of Users Attended a Contest

<https://leetcode.com/problems/percentage-of-users-attended-a-contest>

## Description

Table: `Users`

```
+-------------+---------+
| Column Name | Type    |
+-------------+---------+
| user\_id     | int     |
| user\_name   | varchar |
+-------------+---------+
user\_id is the primary key 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 for this table.
Each row of this table contains the id of a user and the contest they registered into.
```

Write an SQL query 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 query result format is in the following example.

```
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       |
+------------+---------+
Result table:
+------------+------------+
| contest\_id | percentage |
+------------+------------+
| 208        | 100.0      |
| 209        | 100.0      |
| 210        | 100.0      |
| 215        | 66.67      |
| 207        | 33.33      |
+------------+------------+
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%
```

## ac

```java
```


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