MySQL group_concat和count

Question

我试图在一个查询中获取每个类别的各个方面，如下所示：

SELECT b.`id` AS parent_id, b.`name` AS parent_name, 
    a.`id` AS child_id, a.`name` AS child_name, a.`pageid` AS t_id, 
    COUNT( c.`id` ) AS deals_in_cat, 
    d.`aspect_values` AS aspects 
        FROM `category_parent` AS a 
        LEFT JOIN `navigation_filters_weightage` AS d ON a.`id` = d.`cat_id`, 
        `deals_parent_cat` AS b, 
        `deals` AS c 
    WHERE a.`parent_id` = b.`id` 
    AND c.`ebaydeals_category` = a.`id` 
        GROUP BY a.`id`, d.`frequency` 
        ORDER BY b.`order` ASC, a.`order` ASC, d.`frequency` DESC;

这个查询给出了以下结果：

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正如您所看到的，类别的所有方面(在本例中是移动电话)都在一个单独的行中。我想要的是在一个行中获取所有类别的所有方面。因此，我尝试这个查询：

SELECT b.`id` AS parent_id, b.`name` AS parent_name, 
    a.`id` AS child_id, a.`name` AS child_name, a.`pageid` AS t_id, 
    COUNT( c.`id` ) AS deals_in_cat, 
    GROUP_CONCAT( DISTINCT d.`aspect_values` ORDER BY d.`frequency` DESC ) AS aspects 
        FROM `category_parent` AS a 
        LEFT JOIN `navigation_filters_weightage` AS d ON a.`id` = d.`cat_id`, 
        `deals_parent_cat` AS b, 
        `deals` AS c 
    WHERE a.`parent_id` = b.`id` 
    AND c.`ebaydeals_category` = a.`id` 
        GROUP BY a.`id` 
        ORDER BY b.`order` ASC , a.`order` ASC;

这就产生了以下结果：

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正如你所看到的，移动电话的count已经增加了。手机只有271项，但第二次查询几乎将这个数字乘以no。这一类别的各个方面。

我不知道为什么会这样。任何想法都欢迎。

提前谢谢。

Answer 1

表deals中可能有重复的in尝试在计数函数中使用DISTINCT

SELECT b.id AS parent_id, 
    b.name AS parent_name, 
    a.id AS child_id,
    a.name AS child_name, 
    a.pageid AS t_id, 
    count(DISTINCT c.id ) AS deals_in_cat ...