如何在sql中的一列插入父和子记录？

Question

我需要将父列中的父子记录放入其他具有该ID的表中。和 我尝试这样做：

select parent.Parent,child1.child1,Child2.child2 
from parent 
join Child1 on child1.ParentIdId=parent.ParentID 
join Child2 on child1.child1Id=child2.child1Id` 

Create table parent (ParentID int, Parent varchar(10)) 

Create table Child1 (child1Id int, child1 varchar(10), ParentIdId int) 
Create table Child2 (child2Id int, child2 varchar(10), child1Id int) 


insert into parent values(10,'Sony'),(20,'Apple'),(30,'HTC'),(40,'Nexus') 
insert into Child1 values(100,'Sony1',10),(200,'Sony2',10),(300,'Apple1',20),(400,'Apple2',20),(500,'HTC1',30),(600,'HTC2',30), 
(700,'Nexus1',40),(800,'Nexus2',40) 

insert into Child2 values(1000,'Sony11',100),(2000,'Sony22',100),(3000,'Apple11',200),(4000,'Apple22',200),(5000,'HTC11',300),(6000,'HTC22',300), 
(7000,'Nexus11',400),(8000,'Nexus22',400) 

输出我需要：

Ids Products Parents 
10 Sony  null 
20 Apple  null 
30 HTC   null 
40 Nexus  null 
100 Sony1  10 
200 Sony2  10 
300 Apple1  20 
400 Apple2  20 
500 HTC1  30 
600 HTC2  30 
700 Nexus2  40 
800 Nexus2  40 
1000 Sony11 100 
2000 Sony22 100 
3000 Apple11 200 
4000 Apple22 200 
5000 HTC11 300 
6000 HTC22 300 
7000 Nexus11 400 
8000 Nexus22 400 

Answer 1

你可能不得不这样做在3个不同的选择查询像下面

SELECT ParentIds as Ids, 
     Parent as Products, 
     CAST(NULL AS INT) AS Parent 
INTO #Product 
FROM Parent 
UNION ALL 
SELECT child1.child1id, 
     Child1.child1, 
     Child1.ParentId 
FROM parent 
INNER JOIN Child1 on child1.ParentIdId=parent.ParentID 
UNION ALL 
SELECT Child2.Child2Id,child2.child2,Child2.child1Id 
FROM parent 
INNER JOIN Child1 on child1.ParentIdId=parent.ParentID 
INNER JOIN Child2 on child1.child1Id=child2.child1Id` 

Answer 2

我觉得你的例子简单工会都足够了，但我认为你正在寻找递归cte如下：

;with cte (Child, nam, parent) as 
(
    select * from child2 
    union all 
    select * from child1 
    union all 
    select *, null as Parent from parent 
) 
, cte2 as 
(
    select *, 0 as Levl from cte where parent is null 

    union all 

    select c1.*, c2.Levl + 1 as Levl from cte2 c2 join cte c1 
     on c2.child = c1.parent 
) 
select * from cte2 
order by levl 

我已经加入LEVL只是为了了解层次

Answer 3

不使用UNION ALL和多个SELECT语句

SELECT COALESCE(parent.ParentID, Child1.child1id, Child2.child2id), 
     COALESCE(Child2.child2, Child1.child1, parent.Parent), 
     COALESCE(Child1.ParentIdId, Child2.child1id) FROM parent 
FULL JOIN Child1 on 1 = 2 
FULL JOIN Child2 on 1 = 2