Question

这是我正在尝试运行的脚本：

$resultadosPromediados = R::getAll("SELECT count(*) as total, 
                                    SUM(dialogue_score) / total as dialogue_score, 
                                    SUM(consulta_general_score) / total as consulta_general_score, 
                                    SUM(tarea_score) / total as tarea_score, 
                                    SUM(foro_calificacion_score) / total as foro_calificacion_score,  
                                    SUM(foro_respuesta_score) / total as foro_respuesta_score
                                    FROM ranking
                                    WHERE created = :ultima_feha",
                                    array(':ultima_feha' => $fecha));
print_r($resultadosPromediados);

但是我收到了这个错误：

致命错误：未捕获[42S22] - SQLSTATE [42S22]：未找到列：1054第265行/home/ASDFASDF/public_html/ADSFADSF/rb.php中的“字段列表”中未知列“总计”

如何使用总行来划分它们的总和以获得平均读数？

Answer 1

只需使用变量：

SELECT @total := count(*), 
    SUM(dialogue_score) / @total as dialogue_score, 
    SUM(consulta_general_score) / @total as consulta_general_score, 
    SUM(tarea_score) / @total as tarea_score, 
    SUM(foro_calificacion_score) / @total as foro_calificacion_score,  
    SUM(foro_respuesta_score) / @total as foro_respuesta_score
FROM ranking
WHERE created = :ultima_feha

Answer 2

您无法使用在ALIAS语句的同一级别生成的SELECT。你必须选择

一，使用整个表达式，

SELECT  count(*) as total, 
        SUM(dialogue_score) / count(*) as dialogue_score, 
        SUM(consulta_general_score) / count(*) as consulta_general_score, 
        SUM(tarea_score) / count(*) as tarea_score, 
        SUM(foro_calificacion_score) / count(*) as foro_calificacion_score,  
        SUM(foro_respuesta_score) / count(*) as foro_respuesta_score
FROM    ranking
WHERE   created = :ultima_feha

其次，要使用子查询，

SELECT  total,
        dialogue_total / total AS dialogue_score,
        consulta_general_total / total AS consulta_general_score,
        tarea_total / total AS tarea_score,
        foro_calificacion_total / total AS foro_calificacion_score,
        foro_respuesta_total  / total AS foro_respuesta_score
FROM
        (
            SELECT  count(*) as total, 
                    SUM(dialogue_score) as dialogue_total, 
                    SUM(consulta_general_score) as consulta_general_total, 
                    SUM(tarea_score) as tarea_total, 
                    SUM(foro_calificacion_score) as foro_calificacion_total,  
                    SUM(foro_respuesta_score) as foro_respuesta_total
            FROM    ranking
            WHERE   created = :ultima_feha
        ) alias

内联声明MySQL'未知列'

2 个答案: