php - 仅从与类别相关的表中获取有效产品

Question

我有 2 张桌子：

1 Category
- cID
- Name
- Active

2 Products
- pID
- Name
- category_id
- active

这就是我想要的：我想要一个来自只有 ACTIVE 产品的类别的列表。

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 DESC

Answer 1

假设Products.Active = 1意味着活动状态。

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)) 

Answer 2

SELECT * FROM Products
Join Category on Category.ciD = Products.category_id
WHERE Category.Active = 1 AND Products.Active =1

这是假设您的活动列只是 1 或 0。否则根据您存储在那里的值进行调整。

Answer 3

我建议像这样构建
恕我直言，它的语法显示了您真正想看到的内容-所有具有有效产品的类别

select C.cID, C.Name, C.Active
from Category as C
where C.cID in (select distinct T.category_id from Products as T where T.Active = 1)