Question

我有一个MySQL查询，我想在其中添加rank列。

SELECT AM.* , count(ALM.id) as likes FROM admin_models as AM
            left join admin_liked_models as ALM on AM.id = ALM.admin_model_id
            group by AM.id

admin_models和admin_liked_models有一对多关系。

最高likes应为1级。

有人能指出我怎么做吗？谢谢！

Answer 1

不幸的是，MySQL并不支持Row_Number()或其他分析功能。以下是产生相同结果的一种方法：

SELECT *,
    @rn:=@rn+1 rn
FROM (
    SELECT AM.* , count(ALM.id) as likes 
    FROM admin_models as AM
            LEFT JOIN admin_liked_models as ALM ON AM.id = ALM.admin_model_id
    GROUP BY AM.id
) t, (SELECT @rn:=0) t2
ORDER BY likes DESC

您可能不需要子查询，但我只是展示了分离。

Answer 2

这仅适用于使用ORDER BY时，是否无法根据喜欢列数制作排名列？

看起来你不是在寻找rank。如果你不想使用ORDER并希望将等级用作某个等级，你可以尝试这样的事情：

SELECT AM.* , count(ALM.id) as likes,

((SELECT max(maxval) from
   (SELECT count(ALM.id) as maxval  FROM admin_models as AM
        left join admin_liked_models as ALM on AM.id = ALM.admin_model_id
        group by AM.id) as subq) - count(ALM.id) + 1) as rank

FROM admin_models as AM
        left join admin_liked_models as ALM on AM.id = ALM.admin_model_id
        group by AM.id

请注意，在这种情况下，成绩不会是连续的，而且几个型号的成绩相同。

根据列获得排名

2 个答案: