SELECT node.name,(COUNT(parent.name) - (sub_tree.depth + 1)) AS depth
FROM nested_category AS node,nested_category AS parent,nested_category AS sub_parent,(
        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
        AND node.name = 'PORTABLE ELECTRONICS'
        GROUP BY node.name
        ORDER BY node.lft
    )AS sub_tree
WHERE node.lft BETWEEN parent.lft AND parent.rgt
    AND node.lft BETWEEN sub_parent.lft AND sub_parent.rgt
    AND sub_parent.name = sub_tree.name
GROUP BY node.name
HAVING depth <= 1
ORDER BY node.lft;

但是,我做的(这是作弊)是将嵌套集合与邻接列表相结合 – 我在表中嵌入了一个“parent_id”,所以我可以轻松地询问一个节点的子节点.