使用 INNER JOIN 时 MYSQL 中的排序问题

Question

我的查询有问题，我不能用 INNER JOIN 方法正确地编写排序。 我有三张桌子：

产品：

+----+---------------------------------+------------+
| id | name                            | created_at |
+----+---------------------------------+------------+
|  1 | Broth                           | 1673625572 |
|  2 | Skyr                            | 1673982452 |
|  3 | Hamburger                       | 1674060883 |
+----+---------------------------------+------------+

成分

+----+---------+------------+
| id | name    | created_at |
+----+---------+------------+
|  1 | kcal    | 1673982085 |
|  2 | Protein | 1673982085 |
+----+---------+------------+

和关系表：

+----+------------+---------------+--------+----------+-------------+------------+
| id | product_id | ingredient_id | value  | priority | modified_at | created_at |
+----+------------+---------------+--------+----------+-------------+------------+
|  1 |          2 |             1 | 389.00 |        1 |  1673983108 | 1673983108 |
|  2 |          2 |             2 |  71.00 |        1 |  1673983183 | 1673983183 |
|  3 |          1 |             2 |  59.00 |        1 |  1674059830 | 1674059830 |
|  4 |          1 |             1 | 394.00 |        1 |  1674059875 | 1674059875 |
|  5 |          3 |             1 | 366.00 |        1 |  1674060944 | 1674060944 |
|  6 |          3 |             2 |  76.00 |        1 |  1674060944 | 1674060944 |
+----+------------+---------------+--------+----------+-------------+------------+

这是我的查询：

SELECT
    `product`.`name` AS `name`,
    JSON_ARRAYAGG(JSON_OBJECT('name', `ingredient`.`permalink`, 'value', `_related_product_ingredient`.`value` )) AS `ingredients`
FROM
    `_related_product_ingredient`
        INNER JOIN
    `product` ON `product`.`id` = `_related_product_ingredient`.`product_id`
        INNER JOIN
    `ingredient` ON `ingredient`.`id` = `_related_product_ingredient`.`ingredient_id`

GROUP BY `_related_product_ingredient`.`product_id`;

这是一个结果

+---------------------------------+--------------------------------------------------------------------------+
| name                            | ingredients                                                              |
+---------------------------------+--------------------------------------------------------------------------+
| Broth                           | [{"name": "protein", "value": 59.00}, {"name": "kcal", "value": 394.00}] |
| Skyr                            | [{"name": "protein", "value": 71.00}, {"name": "kcal", "value": 389.00}] |
| Hamburger                       | [{"name": "protein", "value": 76.00}, {"name": "kcal", "value": 366.00}] |
+---------------------------------+--------------------------------------------------------------------------+

我希望我的结果按蛋白质值从高到低排序。

有什么建议吗？

Answer 1

您可以通过在查询中添加以下行来按蛋白质值对结果进行排序：

ORDER BY
JSON_EXTRACT(ingredients, '$[1].value') DESC;

所以完整的查询将是：

SELECT
product.name AS name,
JSON_ARRAYAGG(JSON_OBJECT('name', ingredient.permalink, 'value', _related_product_ingredient.value )) AS ingredients
FROM
_related_product_ingredient
INNER JOIN
product ON product.id = _related_product_ingredient.product_id
INNER JOIN
ingredient ON ingredient.id = _related_product_ingredient.ingredient_id
GROUP BY _related_product_ingredient.product_id
ORDER BY
JSON_EXTRACT(ingredients, '$[1].value') DESC;

这将根据成分数组中第二个元素的值对结果进行排序，该元素应对应于蛋白质值。