檢索給定記錄的所有子女和父母

Question

我想檢索給定記錄的所有父母，然後獲取這些父母記錄的所有子女記錄。

對於例如：如果表是一樣的東西，

表1：

Child_Id | Parent_Id 
--------------------- 
    23   4 
    23   5 
    4   20 
    20   21 
    5   12 
    12   15 
    12   17 
    24   30 
    39   4 

鑑於上表id是23那我也來檢索，

21 
    20 
     4 
     23 39 
15 
    12 
     5 
     23 

17 
    12 
     5 
     23 

我嘗試與之前的連接，但它力求幫助我，

SELECT * FROM TABLE1 
CONNECT BY PRIOR CHILD_ID = PARENT_ID 

有什麼辦法可以首先獲得給定節點的所有父母，然後將其父母的所有孩子與兄弟姐妹一起？

Answer 1

您可以使用以下方法來獲取父母/根目錄的列表：

select parent_id as parent 
    from tbl x 
where not exists (select 1 from tbl y where y.child_id = x.parent_id) 

| PARENT | 
|--------| 
|  15 | 
|  21 | 
|  17 | 
|  30 | 

http://sqlfiddle.com/#!4/62c37/18/0

然後對於一個給定根，你可以運行以下命令：

select 21 as parent, 
     listagg(child_id, ' >>> ') within group(order by level) as children 
    from tbl 
start with parent_id = 21 
connect by prior child_id = parent_id 


| PARENT |    CHILDREN | 
|--------|------------------------| 
|  21 | 20 >>> 4 >>> 23 >>> 39 | 

http://sqlfiddle.com/#!4/62c37/35/0

或者如果你不想帶孩子仁到一排，你可以得到類似的輸出到你給運行什麼：

select 21 as parent, 
     lpad(child_id,level*level,' ') as child 
    from tbl 
start with parent_id = 21 
connect by prior child_id = parent_id 


| PARENT |  CHILD | 
|--------|-----------| 
|  21 |   2 | 
|  21 |   4 | 
|  21 |  23 | 
|  21 |  39 | 

http://sqlfiddle.com/#!4/62c37/34/0

我不知道在一個查詢運行它的所有根源，但想我會至少給你等待另一個答案。

但是，如果總是隻有少數幾個孩子（即在10歲以下），那麼這應該是可行的，而不依賴於CONNECT BY，而是使用子查詢。

由於這一做法的一個例子，下面那張8級深，只要有從未超過8個孩子（你可以添加更多的潛艇，如果不是這種情況）在您的整個表應該工作：

with lvl1 as 
(select x.parent_id, x.child_id 
    from tbl x 
    where not exists (select 1 from tbl y where y.child_id = x.parent_id)), 
lvl2 as 
(select x.parent_id, x.child_id 
    from tbl x 
    left join lvl1 
     on x.parent_id = lvl1.child_id), 
lvl3 as 
(select x.parent_id, x.child_id 
    from tbl x 
    left join lvl2 
     on x.parent_id = lvl2.child_id), 
lvl4 as 
(select x.parent_id, x.child_id 
    from tbl x 
    left join lvl3 
     on x.parent_id = lvl3.child_id), 
lvl5 as 
(select x.parent_id, x.child_id 
    from tbl x 
    left join lvl4 
     on x.parent_id = lvl4.child_id), 
lvl6 as 
(select x.parent_id, x.child_id 
    from tbl x 
    left join lvl5 
     on x.parent_id = lvl5.child_id), 
lvl7 as 
(select x.parent_id, x.child_id 
    from tbl x 
    left join lvl6 
     on x.parent_id = lvl6.child_id), 
lvl8 as 
(select x.parent_id, x.child_id 
    from tbl x 
    left join lvl7 
     on x.parent_id = lvl7.child_id) 
select parent_id, 
     case when lag(child2,1) over (partition by parent_id order by parent_id) = child2 then null else child2 end as child2, 
     case when lag(child3,1) over (partition by parent_id order by parent_id) = child3 then null else child3 end as child3, 
     case when lag(child4,1) over (partition by parent_id order by parent_id) = child4 then null else child4 end as child4, 
     case when lag(child5,1) over (partition by parent_id order by parent_id) = child5 then null else child5 end as child5, 
     case when lag(child6,1) over (partition by parent_id order by parent_id) = child6 then null else child6 end as child6, 
     case when lag(child7,1) over (partition by parent_id order by parent_id) = child7 then null else child7 end as child7, 
     case when lag(child8,1) over (partition by parent_id order by parent_id) = child8 then null else child8 end as child8 
from(
select distinct 
     lvl1.parent_id, 
     lvl2.parent_id as child2, 
     nvl(lvl3.parent_id,lvl2.child_id) as child3, 
     nvl(lvl4.parent_id,lvl3.child_id) as child4, 
     nvl(lvl5.parent_id,lvl4.child_id) as child5, 
     nvl(lvl6.parent_id,lvl5.child_id) as child6, 
     nvl(lvl7.parent_id,lvl6.child_id) as child7, 
     nvl(lvl8.parent_id,lvl7.child_id) as child8 
    from lvl1 
    left join lvl2 
    on lvl1.child_id = lvl2.parent_id 
    left join lvl3 
    on lvl2.child_id = lvl3.parent_id 
    left join lvl4 
    on lvl3.child_id = lvl4.parent_id 
    left join lvl5 
    on lvl4.child_id = lvl5.parent_id 
    left join lvl6 
    on lvl5.child_id = lvl6.parent_id 
    left join lvl7 
    on lvl6.child_id = lvl7.parent_id 
    left join lvl8 
    on lvl7.child_id = lvl8.parent_id 
order by parent_id) 

http://sqlfiddle.com/#!4/62c37/50/0

| PARENT_ID | CHILD2 | CHILD3 | CHILD4 | CHILD5 | CHILD6 | CHILD7 | CHILD8 | 
|-----------|--------|--------|--------|--------|--------|--------|--------| 
|  15 |  12 |  5 |  23 | (null) | (null) | (null) | (null) | 
|  17 |  12 |  5 |  23 | (null) | (null) | (null) | (null) | 
|  21 |  20 |  4 |  23 | (null) | (null) | (null) | (null) | 
|  21 | (null) | (null) |  39 | (null) | (null) | (null) | (null) | 
|  30 | (null) | (null) | (null) | (null) | (null) | (null) | (null) |