分组方式，在MySQL中使用

我对mysql查询有问题。 我需要得到最大值评级的全行。 例如，我有表食谱

4.1  | 1 | soup
4.2 | 3 | soup
4.9 | 4 | soup
4.8 | 5 | salads
4.3 | 6 | dishes9

SELECT MAX(rating) rat, id, class FROM recipes GROUP BY class

4.9 | 1 | soup
4.8 | 5 | salads
4.3 | 6 | dishes

4.8 | 5 | salads
4.3 | 6 | dishes

评级| id |等级

4.1  | 1 | soup
4.2 | 3 | soup
4.9 | 4 | soup
4.8 | 5 | salads
4.3 | 6 | dishes9

SELECT MAX(rating) rat, id, class FROM recipes GROUP BY class

4.9 | 1 | soup
4.8 | 5 | salads
4.3 | 6 | dishes

4.8 | 5 | salads
4.3 | 6 | dishes

我得到的结果是：

rat|id|class

4.1  | 1 | soup
4.2 | 3 | soup
4.9 | 4 | soup
4.8 | 5 | salads
4.3 | 6 | dishes9

SELECT MAX(rating) rat, id, class FROM recipes GROUP BY class

4.9 | 1 | soup
4.8 | 5 | salads
4.3 | 6 | dishes

4.8 | 5 | salads
4.3 | 6 | dishes

所以在第一行（其中class='soup'）中，我得到了truly max评级-4.9，但在这一行中，id的值是1，而不是4

当我使用拥有

SELECT MAX(rating) rat, id, class FROM recipes GROUP BY class HAVING rating=rat

结果变成

rat|id|class

4.1  | 1 | soup
4.2 | 3 | soup
4.9 | 4 | soup
4.8 | 5 | salads
4.3 | 6 | dishes9

SELECT MAX(rating) rat, id, class FROM recipes GROUP BY class

4.9 | 1 | soup
4.8 | 5 | salads
4.3 | 6 | dishes

4.8 | 5 | salads
4.3 | 6 | dishes

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有人能帮我解决这个问题吗？

一种方法是使用

IN（）

子查询找到

MAX（rat）

行中相应的

id

s

SELECT * 
FROM recipes
WHERE id IN (
  SELECT id FROM recipes GROUP BY class HAVING rat = MAX(rat)
)

请尝试此查询-

SELECT r1.*  FROM recipes r1
  JOIN (SELECT MAX(rating) rat, class FROM recipes GROUP BY class) r2
    ON r1.class = r2.class AND r1.rating = r2.rat;

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如果您有两个相同级别的id，且具有相同的最大评级，您希望得到什么。例如，在第一个列表中，如果添加第4.9 | 7 | soup行，是否同时返回第4行和第7行？还是随便挑一个？