如何从SQL中的表中获取父节点的子节点?

时间:2015-03-19 23:34:27

标签: sql tsql hierarchyid

假设我的数据库中有以下层次结构表示:

A
|_B_C
|_D

然后我想从A(或B)获取子节点。 反之亦然,我想从给定的子节点获取父节点? <>

CREATE TABLE tbl (
   Node HierarchyID PRIMARY KEY CLUSTERED,
   NodeLevel AS Node.GetLevel(),
   ID INT UNIQUE NOT NULL,
   Name VARCHAR(50) NOT NULL
 ) 

插入根目录:

INSERT INTO tbl (Node, ID, Name)
   VALUES (HierarchyId::GetRoot(), 1, 'A') 

孩子B

DECLARE @parent HierarchyId = HierarchyId::GetRoot()
INSERT INTO tbl (Node,ID,Name) VALUES (@parent.GetDescendant(NULL,NULL),2,'B')

1 个答案:

答案 0 :(得分:0)

select @child = node from tbl where id = 2;
-- get immediate ancestor
select * from dbo.tbl where Node = @child.GetAncestor(1);

-- get immediate children
select
    *
from
    dbo.tbl
where
    Node.IsDescendantOf(@parent) = 1 and 
    Node.GetLevel() = @parent.GetLevel() + 1;