sql - 按具有产品数量的子节点过滤

Question

以下 SQL 代码工作正常，但我无法选择/过滤类别。带来所有类别。

举个例子，

Cars (20) (root)
---> Blue cars (12)
----------> Ford (2)
----------> Bmw (9)
----------> Dodge (1)
---> Red cars (9)
----------> Xxxx (9)
---> Black cars (1)
----------> Yy (1)

如何仅选择蓝色汽车的类别。（带子节点）

我如何更改这个可以完成的 sql 代码？

我希望结果如下。（如果我选择蓝色汽车类别）

---> blue cars (12)
----------> ford (2)
----------> bmw (9)
----------> dodge (1)

这是sql代码...

SELECT 
parent.cid,
parent.title,
(SELECT COUNT(parent2.cid) FROM categories AS parent2 WHERE parent.lft > parent2.lft AND parent.rgt < parent2.rgt) AS depth,
COUNT(products.cat_id) AS total

FROM categories AS node,
categories AS parent,
products

WHERE 

node.lft BETWEEN parent.lft AND parent.rgt 

AND node.cid = products.cat_id

GROUP BY parent.cid having depth <= 5
ORDER BY parent.lft

Answer 1

我认为你一直在想这个 - 获取子树是关于嵌套集的简单化操作

SELECT *
FROM categories
WHERE lft BETWEEN bluecarleftvalue AND bluecarrightvalue
ORDER BY lft ASC