分层查询，账户树

Question

我在搜索父或子帐户时遇到了分层查询，通常让我们假设一个示例：

表帐户：

Account    Parent
217518     217518 or null
304229     217518
424590     217518
378327     217518
491504     378327
234123     491504

所以层次结构看起来：

现在，我得到了表格“SHOW_PARENT_CHILD_ACC”，我将在其中插入我想显示的帐户。 （我需要在分层查询中使用它）

插入 Show_parent_child_acc(acc) 值 (304229)。

查询应返回所有帐户 ID，因此：

304229     
424590     
378327 
217518    
491504     
234123     

我会的时候也一样 插入 show_parent_cild_acc(acc) 值 (234123)

查询应返回所有帐户 ID，因此：

304229     
424590     
378327 
217518    
491504     
234123  

换句话说，无论我将哪个帐户（父母/孩子或孩子的孩子）插入到 show_parent_child_acc 表中。查询应该返回整个帐户层次结构

现在我有类似的东西：

WITH acc_to_delete( ID ) AS (
                            select case when parentaccount is null then accountid else parentaccount end from account where accountid in                                          
                                 (select acc from show_parent_child_acc) 
                          )
                          SELECT accountid id_acc,case when parentaccount is null then accountid else parentaccount end parentaccount
                          FROM   account p
                          START WITH
                           EXISTS( SELECT 'X'
                                    FROM   acc_to_delete w
                                    WHERE  p.accountid = w.ID
                                    )
                          CONNECT BY accountid = PRIOR parentaccount
                          union
                          SELECT accountid id_acc,case when parentaccount is null then accountid else parentaccount end parentaccount
                          FROM   account p
                          START WITH
                          EXISTS( SELECT 'X'
                                    FROM   acc_to_delete w
                                    WHERE  p.accountid = w.ID
                                    )
                          CONNECT BY PRIOR accountid = parentaccount 
                      

但它没有按预期工作（它在我放入 SHOW_PARENT_CHILD_ACC 的地方工作正常：217518..）

Answer 1

我将从查找根 id（子查询“root”）开始，然后创建典型的层次结构：

with 
  tmp as (select acc from show_parent_child_acc ),
  root as (
    select max(acnt) keep (dense_rank last order by lvl) root
      from (
        select nvl(parentaccount, accountid) acnt, level lvl  
          from account a cross join tmp
          connect by nocycle prior parentaccount = accountid
          start with accountid = acc or parentaccount = acc ))
select accountid from account cross join root
  connect by nocycle prior accountid = parentaccount
  start with parentaccount = root.root
union select root from root

测试数据和输出：

create table account (accountid number(8), parentaccount number(8));
insert into account values (217518, 217518);
insert into account values (304229, 217518);
insert into account values (424590, 217518);
insert into account values (378327, 217518);
insert into account values (491504, 378327);
insert into account values (234123, 491504);
create table show_parent_child_acc (acc number(8));
insert into show_parent_child_acc values (234123);

AccountID
---------
   217518
   234123
   304229
   378327
   424590
   491504

Answer 2

进一步修改原始查询如下。

WITH acc_to_delete( ID ) AS (
                        select case when parentaccount is null then accountid else parentaccount end from account where accountid in                                          
                             (select acc from show_parent_child_acc) 
                      )                      
SELECT DISTINCT accountid id_acc, case when parentaccount is null then accountid else parentaccount end parentaccount 
FROM account START WITH parentaccount in
(                          
    SELECT case when parentaccount is null then accountid else parentaccount end parentaccount
    FROM   account p 
    START WITH
    EXISTS( SELECT 'X'
            FROM   acc_to_delete w
            WHERE  p.accountid = w.ID
        )
    CONNECT BY nocycle accountid = PRIOR parentaccount 
    UNION
    SELECT case when parentaccount is null then accountid else parentaccount end parentaccount
    FROM   account p 
    START WITH
    EXISTS( SELECT 'X'
            FROM   acc_to_delete w
            WHERE  p.accountid = w.ID
            )
    CONNECT BY nocycle PRIOR accountid =  parentaccount
) 
CONNECT BY NOCYCLE parentaccount = PRIOR accountid

主要是收集所有对应的父母，然后得到他们的孩子。