带有 WHERE 子句的 Rank() 函数不显示任何内容 MYSQL

Question

所以我必须从他们的每个组织中找到学生的最高分数，我通过应用 RANK() 函数提出了解决方案：

SET SQL_SAFE_UPDATES = 0;

INSERT INTO interviewqs.details(scores,name,organization)
    VALUES
    (30,"Daniel","OWARD UNI"),
    (40,"Kayla","OWARD UNI"),
    (12,"Hope","ZELENSKY UNI"),
    (50,"Osman","ZELENSKY UNI"),
    (4,"Daniel","REWARD UNI"),
    (77,"Joe","REWARD UNI");
DESCRIBE interviewqs.details;

# Find the student with highest scores from each organization
    
SELECT DISTINCT organization,name,scores,
    RANK() OVER (PARTITION BY organization ORDER BY scores DESC)
        AS "rank"
        FROM details
        WHERE "rank" = 1;

问题是当我执行代码时输出显示为空 table,

没有应用 'WHERE' 函数

organization name scores rank 
OWARD UNI   Kayla   40  1
OWARD UNI   Daniel  30  3
REWARD UNI  Daniel  77  1
REWARD UNI  Daniel  30  2
REWARD UNI  Daniel  4   4
ZELENSKY UNI Osman  50  1
ZELENSKY UNI Hope   12  3

应用了 'WHERE' 函数

organization name scores rank

我这里做错了什么？

Answer 1

您不能在 WHERE 子句中使用 window 函数。原因是 WHERE 子句在 window 函数之前先被处理。我强烈建议您阅读一篇文章，Why Can't I use RANK() in Where Clause

要解决此问题，请将查询更改为使用 CTE 或子查询，如下所示：

子查询：

SELECT organization, name, scores
FROM (
    SELECT 
        organization, name, scores,
        RANK() OVER(PARTITION BY organization ORDER BY scores DESC) AS rnk
    FROM details
) tmp
WHERE rnk = 1

Answer 2

SELECT DISTINCT
       organization,
       FIRST_VALUE(name) OVER (PARTITION BY organization ORDER BY scores DESC) name,
       MAX(scores) OVER (PARTITION BY organization) scores
FROM details

Answer 3

这是使用 CTE 的另一种方式。

WITH tmp AS 
(
  SELECT DISTINCT organization, `name`, scores,
  RANK() OVER (PARTITION BY organization ORDER BY scores DESC) `rank`
  FROM details
)
SELECT organization, `name`, scores FROM tmp WHERE `rank` = 1;

DB Fiddle

注意：rank是保留字，使用时一定要小心，一定要放在反引号中。

查看 MySQL Common Table Expression 了解有关 CTE 的更多详细信息。

In MySQL, every statement or query produces a temporary result or relation. A common table expression or CTE is used to name those temporary results set that exist within the execution scope of that particular statement

带有 WHERE 子句的 Rank() 函数不显示任何内容 MYSQL

Rank() function with WHERE clause display nothing MYSQL

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