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104 lines
3.2 KiB
HTML
104 lines
3.2 KiB
HTML
<p>表：<code>Movies</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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| movie_id | int |
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| title | varchar |
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+---------------+---------+
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movie_id 是这个表的主键(具有唯一值的列)。
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title 是电影的名字。
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</pre>
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<p>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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| name | varchar |
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+---------------+---------+
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user_id 是表的主键(具有唯一值的列)。
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</pre>
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<p>表：<code>MovieRating</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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| movie_id | int |
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| user_id | int |
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| rating | int |
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| created_at | date |
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+---------------+---------+
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(movie_id, user_id) 是这个表的主键(具有唯一值的列的组合)。
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这个表包含用户在其评论中对电影的评分 rating 。
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created_at 是用户的点评日期。
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</pre>
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<p> </p>
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<p>请你编写一个解决方案：</p>
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<ul>
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<li>查找评论电影数量最多的用户名。如果出现平局，返回字典序较小的用户名。</li>
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<li>查找在 <code>February 2020</code><strong> 平均评分最高</strong> 的电影名称。如果出现平局，返回字典序较小的电影名称。</li>
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</ul>
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<p><strong>字典序</strong> ，即按字母在字典中出现顺序对字符串排序，字典序较小则意味着排序靠前。</p>
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<p>返回结果格式如下例所示。</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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<strong>输入：</strong>
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Movies 表：
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+-------------+--------------+
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| movie_id | title |
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+-------------+--------------+
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| 1 | Avengers |
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| 2 | Frozen 2 |
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| 3 | Joker |
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+-------------+--------------+
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Users 表：
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+-------------+--------------+
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| user_id | name |
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+-------------+--------------+
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| 1 | Daniel |
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| 2 | Monica |
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| 3 | Maria |
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| 4 | James |
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+-------------+--------------+
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MovieRating 表：
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+-------------+--------------+--------------+-------------+
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| movie_id | user_id | rating | created_at |
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+-------------+--------------+--------------+-------------+
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| 1 | 1 | 3 | 2020-01-12 |
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| 1 | 2 | 4 | 2020-02-11 |
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| 1 | 3 | 2 | 2020-02-12 |
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| 1 | 4 | 1 | 2020-01-01 |
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| 2 | 1 | 5 | 2020-02-17 |
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| 2 | 2 | 2 | 2020-02-01 |
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| 2 | 3 | 2 | 2020-03-01 |
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| 3 | 1 | 3 | 2020-02-22 |
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| 3 | 2 | 4 | 2020-02-25 |
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+-------------+--------------+--------------+-------------+
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<strong>输出：</strong>
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Result 表：
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+--------------+
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| results |
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+--------------+
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| Daniel |
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| Frozen 2 |
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+--------------+
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<strong>解释：</strong>
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Daniel 和 Monica 都点评了 3 部电影（"Avengers", "Frozen 2" 和 "Joker"） 但是 Daniel 字典序比较小。
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Frozen 2 和 Joker 在 2 月的评分都是 3.5，但是 Frozen 2 的字典序比较小。
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</pre>
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