Question

我有一个这样的表（通过连接不同的表创建）

+------------+--------------+-------------+
| product_id | product_name | category_id |
+------------+--------------+-------------+
|     1      |    orange    |      3      |
|     1      |    orange    |      4      |
|     2      |    banana    |      2      |
|     3      |    apple     |      2      |
|     3      |    apple     |      3      |
|     3      |    apple     |      4      |
+------------+--------------+-------------+

我希望它按ID组合在一起，但按名称排序。

喜欢这个

+------------+--------------+-------------+
| product_id | product_name | category_id |
+------------+--------------+-------------+
|     3      |    apple     |      2      |
|     3      |    apple     |      3      |
|     3      |    apple     |      4      |
|     2      |    banana    |      2      |
|     1      |    orange    |      3      |
|     1      |    orange    |      4      |
+------------+--------------+-------------+

这可能吗？我尝试使用GROUP BY，但是每个产品只保留一行，所以我看不到所有类别的产品。

编辑：我的查询到目前为止

SELECT products.id as product_id, products.name as product_name, categories.id as category_id
FROM produkte
    LEFT JOIN prod_cat ON products.id = prod_cat.product_id
    JOIN categories ON prod_cat.category_id = categories.id
ORDER BY products.id

“prod_cat”是为产品分配类别的表。

Answer 1

Select * from products order by product_id desc, product_name asc;

Answer 2

这将按名称和类别ID对它们进行排序，并按照您显示的结果给出结果。

SELECT products.id as product_id, products.name as product_name, categories.id as category_id
FROM produkte
    LEFT JOIN prod_cat ON products.id = prod_cat.product_id
    JOIN categories ON prod_cat.category_id = categories.id
ORDER BY product_name ASC, category_id ASC

我认为您误解了GROUP BY，但如果您想对它们进行分组（将记录减少到GROUP BY子句中给出的字段匹配的记录），您可以使用GROUP_CONCAT(categories.id)将类别显示为列表与GROUP BY product_id

按ID分组，但按名称排序

2 个答案: