Question

按照article的说明，我希望获得一个完整的树，每个类别的深度都可以正常工作。

我也希望得到每个类别的产品数量。我尝试添加另一个COUNT（products_categories.product_id），但它搞砸了深度值。如何修改查询以获取每个类别的产品数量和深度？

products_categories
----------------------
category_id
product_id


SELECT node.name, (COUNT(parent.name) - 1) AS depth
FROM nested_category AS node,
    nested_category AS parent
 WHERE node.lft BETWEEN parent.lft AND parent.rgt
 GROUP BY node.name
 ORDER BY node.lft

换句话说，我想结合这两个查询。

SELECT node.name, (COUNT(parent.name) - 1) AS depth
FROM nested_category AS node,
    nested_category AS parent
WHERE node.lft BETWEEN parent.lft AND parent.rgt
GROUP BY node.name
ORDER BY node.lft

SELECT parent.name, COUNT(product.name)
FROM nested_category AS node ,
    nested_category AS parent,
    product
WHERE node.lft BETWEEN parent.lft AND parent.rgt
    AND node.category_id = product.category_id
GROUP BY parent.name
ORDER BY node.lft;

Answer 1

我终于解决了我的问题。我结合了上面的查询，这样我就可以获得深度和产品数量。

SELECT parent.id,
                   parent.lft,
                   parent.rgt,
                   (SELECT COUNT(parent2.id) FROM businesscategories AS parent2 WHERE parent.lft > parent2.lft AND parent.rgt < parent2.rgt) AS depth,
                   COUNT(b_c.business_id) AS bcount

                FROM businesscategories AS node,
                businesscategories AS parent,
                businesses_categories AS b_c,
                WHERE node.lft BETWEEN parent.lft AND parent.rgt AND node.id = b_c.category_id
                GROUP BY parent.id having depth > 0
                ORDER BY parent.lft

一个查询中的嵌套集，产品计数和类别深度

1 个答案: