I m using the MPTT (modised preorder Gang transersal) model tostor data in mySQL table. (MPTT模型:另一个说明是 封套式)。 我的问题是:是否有任何人 figure清树 que果? 我只能按标签填写ER,但结果将按标签分类,不尊重树木的子点或深度。

这里有一个例子,即我用来找回一个任意的 no树,每个 no子深度:

SELECT node.id, (COUNT(parent.id) - (sub_tree.depth + 1)) AS depth
FROM person AS node,
person AS parent,
person AS sub_parent, (
    SELECT node.id, (COUNT(parent.id) - 1) AS depth
    FROM person AS node,
    person AS parent
    WHERE node.lft BETWEEN parent.lft AND parent.rgt
    AND node.id = 1 // that s my root object
    GROUP BY node.id, node.lft
    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.id = sub_tree.id 
GROUP BY node.id
ORDER BY node.lft

http://mikehillyer.com/articles/managing-hierarchical-data-in-mysql/"rel=“nofollow noretinger” http://mikehillyer.com/articles/managing-hierarchical-data-in-mysql/。