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81 lines
2.3 KiB
HTML
81 lines
2.3 KiB
HTML
<p>用户表: <code>Users</code></p>
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<pre>
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+-------------+---------+
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| Column Name | Type |
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+-------------+---------+
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| user_id | int |
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| user_name | varchar |
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+-------------+---------+
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user_id 是该表的主键(具有唯一值的列)。
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该表中的每行包括用户 ID 和用户名。</pre>
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<p> </p>
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<p>注册表: <code>Register</code></p>
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<pre>
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+-------------+---------+
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| Column Name | Type |
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+-------------+---------+
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| contest_id | int |
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| user_id | int |
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+-------------+---------+
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(contest_id, user_id) 是该表的主键(具有唯一值的列的组合)。
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该表中的每行包含用户的 ID 和他们注册的赛事。</pre>
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<p> </p>
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<p>编写解决方案统计出各赛事的用户注册百分率,保留两位小数。</p>
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<p>返回的结果表按 <code>percentage</code> 的 <strong>降序 </strong>排序,若相同则按 <code>contest_id</code> 的 <strong>升序 </strong>排序。</p>
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<p>返回结果如下示例所示。</p>
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<p> </p>
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<p><strong>示例 1:</strong></p>
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<pre>
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<code><strong>输入:</strong>
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Users</code> 表:
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+---------+-----------+
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| user_id | user_name |
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+---------+-----------+
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| 6 | Alice |
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| 2 | Bob |
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| 7 | Alex |
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+---------+-----------+
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<code>Register</code> 表:
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+------------+---------+
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| contest_id | user_id |
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+------------+---------+
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| 215 | 6 |
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| 209 | 2 |
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| 208 | 2 |
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| 210 | 6 |
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| 208 | 6 |
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| 209 | 7 |
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| 209 | 6 |
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| 215 | 7 |
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| 208 | 7 |
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| 210 | 2 |
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| 207 | 2 |
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| 210 | 7 |
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+------------+---------+
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<strong>输出:</strong>
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+------------+------------+
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| contest_id | percentage |
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+------------+------------+
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| 208 | 100.0 |
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| 209 | 100.0 |
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| 210 | 100.0 |
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| 215 | 66.67 |
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| 207 | 33.33 |
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+------------+------------+
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<strong>解释:</strong>
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所有用户都注册了 208、209 和 210 赛事,因此这些赛事的注册率为 100% ,我们按 contest_id 的降序排序加入结果表中。
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Alice 和 Alex 注册了 215 赛事,注册率为 ((2/3) * 100) = 66.67%
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Bob 注册了 207 赛事,注册率为 ((1/3) * 100) = 33.33%</pre>
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