DENSE_RANK

返回当前行的排名，排名不留间隔。该值是当前行所在的同级组在其分区内的编号。排序列的值相等的行获得相同的排名，下一个排名值总是加 1（不留间隔）。

行按照窗口定义中 ORDER BY 子句定义的顺序从 1 开始编号。如果没有 ORDER BY 子句，则所有行都被视为同级行，该函数始终返回 1。

另请参阅： [SELECT] [ROW_NUMBER] [RANK]

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语法

SELECT DENSE_RANK() OVER ([PARTITION BY column] ORDER BY column [ASC|DESC])
FROM <multipartIdentifier>;

参数

PARTITION BY column 可选。将结果集划分为多个分区。DENSE_RANK 函数分别应用于每个分区。

ORDER BY column 指定分配排名的顺序。如果没有 ORDER BY 子句，则所有行都被视为同级行，排名均为 1。

返回值

返回一个整数，表示当前行在分区内的密集排名，并列的值不会产生间隔。

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示例

按贡献数对贡献者排名（不留间隔）

-- Rank contributors without gaps for ties
SELECT
    DENSE_RANK() OVER (ORDER BY contributions DESC) as rank,
    login,
    contributions,
    html_url
FROM github.repos.contributors
WHERE owner = 'stackql'
  AND repo IN ('stackql', 'stackql-deploy', 'stackql-provider-registry')
ORDER BY contributions DESC;

比较 DENSE_RANK 与 RANK 和 ROW_NUMBER

-- Compare RANK vs DENSE_RANK vs ROW_NUMBER for contributors
SELECT
    login,
    contributions,
    RANK() OVER (ORDER BY contributions DESC) as rank,
    DENSE_RANK() OVER (ORDER BY contributions DESC) as dense_rank,
    ROW_NUMBER() OVER (ORDER BY contributions DESC) as row_num
FROM github.repos.contributors
WHERE owner = 'stackql'
  AND repo = 'stackql';

对跨多个仓库聚合的贡献数排名

-- Rank total contributions across multiple repos
WITH all_contributors AS (
    SELECT login, contributions, html_url
    FROM github.repos.contributors
    WHERE owner = 'stackql' AND repo = 'stackql'
    UNION ALL
    SELECT login, contributions, html_url
    FROM github.repos.contributors
    WHERE owner = 'stackql' AND repo = 'stackql-deploy'
    UNION ALL
    SELECT login, contributions, html_url
    FROM github.repos.contributors
    WHERE owner = 'stackql' AND repo = 'stackql-provider-registry'
)
SELECT
    DENSE_RANK() OVER (ORDER BY SUM(contributions) DESC) as rank,
    login,
    SUM(contributions) as total_contributions,
    MAX(html_url) as html_url
FROM all_contributors
GROUP BY login
ORDER BY total_contributions DESC;

有关更多信息，请参阅 https://sqlite.org/windowfunctions.html#built-in_window_functions。