database - 我想要我传递的节点的所有级别的节点以子句开头

Question

假设以下是层次结构：

我正在通过5，所以我除了 5,4,2,1 我该怎么做。提前致谢。

Answer 1

如果你想要所有的祖先和兄弟姐妹，那么在子句中5使用 parent id ：start with

/* sample data
with t(id, pid) as (
    select 1, null from dual union all
    select 2,    1 from dual union all
    select 3,    1 from dual union all
    select 4,    2 from dual union all
    select 5,    2 from dual union all
    select 6,    3 from dual ) */ 
select distinct id
  from t connect by prior pid = id
  start with pid = (select pid from t where id = 5)