我有表它存储层次结构数据在MySQL这个表存储稳定关系但如果每个用户少于1000个购买删除而用户用户较低级别替换这是我的代码并且工作正常，在GROUP BY之后它包含所有后代的祖先与比较，然后COUNT(*) AS level计数每个用户的水平。这个我有SQL代码压缩数据根据每个用户的最小购买
+-------------+---------------+-------------+
| ancestor_id | descendant_id | path_length |
+-------------+---------------+-------------+
| 1 | 1 | 0 |
| 1 | 2 | 1 |
| 1 | 3 | 1 |
| 1 | 4 | 2 |
| 1 | 5 | 3 |
| 1 | 6 | 4 |
| 2 | 2 | 0 |
| 2 | 4 | 1 |
| 2 | 5 | 2 |
| 2 | 6 | 3 |
| 3 | 3 | 0 |
| 4 | 4 | 0 |
| 4 | 5 | 1 |
| 4 | 6 | 2 |
| 5 | 5 | 0 |
| 5 | 6 | 1 |
| 6 | 6 | 0 |
+-------------+---------------+-------------+
这是表购买
+--------+--------+
| userid | amount |
+--------+--------+
| 2 | 2000 |
| 4 | 6000 |
| 6 | 7000 |
| 1 | 7000 |
SQL代码
SELECT a.*
FROM
( SELECT userid
FROM webineh_user_buys
GROUP BY userid
HAVING SUM(amount) >= 1000
) AS buys_d
JOIN
webineh_prefix_nodes_paths AS a
ON a.descendant_id = buys_d.userid
JOIN
(
SELECT userid
FROM webineh_user_buys
GROUP BY userid
HAVING SUM(amount) >= 1000
) AS buys_a on (a.ancestor_id = buys_a.userid )
JOIN
( SELECT descendant_id
, MAX(path_length) path_length
FROM webineh_prefix_nodes_paths
where a.ancestor_id = ancestor_id
GROUP
BY descendant_id
) b
ON b.descendant_id = a.descendant_id
AND b.path_length = a.path_length
GROUP BY a.descendant_id, a.ancestor_id
我需要获取max path_length，其中ancestor_id至少有1000个购买但在子查询中的位置有错误a.ancestor_id = ancestor_id错误代码
1054 - 'where子句'中的未知列'a.ancestor_id'
我添加SQLFidle演示。
答案 0 :(得分：0)
您可以使用此查询：
class Solution {
public:
vector<vector<int>> levelOrder(TreeNode* root) {
vector< vector<int> > res;
TreeNode* ptr;
queue<TreeNode*> q;
vector<int> v;
if(root){
q.push(root);
q.push(NULL);
}
while(!(q.empty())){
ptr = q.front();
q.pop();
if(q.empty())
break;
if(ptr){
if(ptr->left)
q.push(ptr->left);
if(ptr->right)
q.push(ptr->right);
v.push_back(ptr->val);
}
else {
q.push(NULL);
res.push_back(v);
v.clear();
}
}
return res;
}
};
问题中样本数据的输出：
select m.userid as descendant,
p.ancestor_id,
p.path_length
from (
select b1.userid,
min(case when b2.amount >= 1000
then p.path_length
end) as path_length
from (select userid, sum(amount) amount
from webineh_user_buys
group by userid
having sum(amount) >= 1000
) as b1
left join webineh_prefix_nodes_paths p
on p.descendant_id = b1.userid
and p.path_length > 0
left join (select userid, sum(amount) amount
from webineh_user_buys
group by userid) as b2
on p.ancestor_id = b2.userid
group by b1.userid
) as m
left join webineh_prefix_nodes_paths p
on p.descendant_id = m.userid
and p.path_length = m.path_length
order by m.userid