mysql - #1111 - 组函数使用无效 - MYSQL

Question

嗯，我正在使用以下查询，但是我收到以下错误(#1111 - 组函数的无效使用)。这是查询:

SELECT 
    a.`wo_number`,
    a.`crew_est`,
    a.`manhour_est`,
    b.`act_hours`,
    a.`status`,
    SUM(CASE
        WHEN a.`status` = 'FINISH' THEN SUM(a.`status`)
        ELSE 0
    END) / SUM(a.`crew_est` * a.`manhour_est`) AS `total_percentage`
FROM
    `table_a` AS a
        LEFT JOIN
    `table_b` AS b ON a.`wo_number` = b.`wo_number`
WHERE
    a.`wo_number` = 'some_number'
GROUP BY a.`wo_number` , a.`sheet` , a.`serial`

如果我删除 CASE WHEN THEN 内的 SUM()，则查询有效。但是，我没有得到满足我需要的准确结果。

任何帮助将不胜感激。谢谢。

Answer 1

您正在嵌套 SUM 函数，这是不允许的。

您可能想要这个:

SELECT 
    a.`wo_number`,
    a.`crew_est`,
    a.`manhour_est`,
    b.`act_hours`,
    a.`status`,
    SUM(CASE
        WHEN a.`status` = 'FINISH' THEN 1 -- or the column you want to aggregate
    END) / SUM(a.`crew_est` * a.`manhour_est`) AS `total_percentage`
FROM
    `table_a` AS a
        LEFT JOIN
    `table_b` AS b ON a.`wo_number` = b.`wo_number`
WHERE
    a.`wo_number` = 'some_number'
GROUP BY a.`wo_number` , a.`sheet` , a.`serial`

另外，简写

SUM(CASE
        WHEN a.`status` = 'FINISH' THEN 1
    END)

是

SUM(a.`status` = 'FINISH')