SELECT
node.account_id,
node.name,
node.acc_num,
node.debit,
node.credit,
node.balance,
(COUNT(parent.name) - 1) AS level,
node.lft,
node.rgt
FROM accounts AS node,
accounts AS parent
WHERE node.lft BETWEEN parent.lft AND parent.rgt
GROUP BY node.name
ORDER BY node.lft;
请大为前辈指解析这个求树的深度的语句?也就是level的值是怎么得出来的?
node.account_id,
node.name,
node.acc_num,
node.debit,
node.credit,
node.balance,
(COUNT(parent.name) - 1) AS level,
node.lft,
node.rgt
FROM accounts AS node,
accounts AS parent
WHERE node.lft BETWEEN parent.lft AND parent.rgt
GROUP BY node.name
ORDER BY node.lft;
请大为前辈指解析这个求树的深度的语句?也就是level的值是怎么得出来的?
如果需要可以通过程序或者存储过程实现。