Question

我有以下SQL查询，它会计算ID为 1800 的项目的前 100 条目的平均得分。我想概括它来计算每个项目的顶部 100 条目的平均得分，所以如果有10个项目，将要处理的记录数量将是1000，其中每100个对应于一个不同的project_id。任何帮助将不胜感激！

  SELECT 
    score1.project_id, AVG(score1.final_score)
FROM
    (SELECT 
        project_id, final_score
    FROM
        consultant_project_score
    WHERE
        project_id = 1800
    ORDER BY final_score DESC
    LIMIT 100) score1;

Answer 1

在计算函数中计算平均值的逻辑，并在表格的select查询中调用它。

select project_id,calaverage(project_id) as `average`
from
consultant_project_score

可以按如下方式创建平均函数：

CREATE 
    FUNCTION `calaverage`(projectid INT)
    RETURNS FLOAT
    BEGIN
    DECLARE average FLOAT;
    SELECT 
    AVG(score1.final_score) INTO average
    FROM
    (SELECT 
        project_id, final_score
    FROM
        consultant_project_score
    WHERE
        project_id = projectid
    ORDER BY final_score DESC
    LIMIT 100) score1;
    RETURN average;
    END

SQL：概括查询

1 个答案: