php - 仅从与类别相关的表中获取事件产品

Question

我有 2 个表:

1 Category
- cID
- Name
- Active

2 Products
- pID
- Name
- category_id
- active

这是我想要的:我想要一份只有活跃产品的类别列表。

提前致谢

解决方案:SELECT DISTINCT category.* FROM category INNER JOIN products ON category.id = products.c_id WHERE products.active = 0 ORDER BY category.id 降序

Answer 1

假设 Products.Active = 1 表示事件状态。

SELECT c.*
FROM Category c
INNER JOIN Products p ON c.CID = p.category_id
GROUP BY c.CID
HAVING COUNT(*) = SUM(IF(p.Active = 1, 1, 0))