mirror of https://github.com/dunwu/db-tutorial.git
56 lines
1.4 KiB
SQL
56 lines
1.4 KiB
SQL
-- 分数排名
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--
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-- 编写一个 SQL 查询来实现分数排名。如果两个分数相同，则两个分数排名（Rank）相同。
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-- 请注意，平分后的下一个名次应该是下一个连续的整数值。换句话说，名次之间不应该有“间隔”。
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--
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-- +----+-------+
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-- | Id | Score |
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-- +----+-------+
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-- | 1 | 3.50 |
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-- | 2 | 3.65 |
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-- | 3 | 4.00 |
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-- | 4 | 3.85 |
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-- | 5 | 4.00 |
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-- | 6 | 3.65 |
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-- +----+-------+
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-- 例如，根据上述给定的 Scores 表，你的查询应该返回（按分数从高到低排列）：
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--
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-- +-------+------+
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-- | Score | Rank |
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-- +-------+------+
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-- | 4.00 | 1 |
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-- | 4.00 | 1 |
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-- | 3.85 | 2 |
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-- | 3.65 | 3 |
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-- | 3.65 | 3 |
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-- | 3.50 | 4 |
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-- +-------+------+
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USE db_tutorial;
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CREATE TABLE IF NOT EXISTS scores (
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id INT PRIMARY KEY AUTO_INCREMENT,
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score DOUBLE
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);
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INSERT INTO scores (score)
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VALUES (3.50);
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INSERT INTO scores (score)
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VALUES (3.65);
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INSERT INTO scores (score)
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VALUES (4.00);
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INSERT INTO scores (score)
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VALUES (3.85);
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INSERT INTO scores (score)
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VALUES (4.00);
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INSERT INTO scores (score)
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VALUES (3.65);
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SELECT count(DISTINCT b.score)
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FROM scores b;
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SELECT a.score AS score,
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(SELECT count(DISTINCT b.score) FROM scores b WHERE b.score >= a.score) AS ranking
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FROM scores a
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ORDER BY a.score DESC;
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