我有一个包含NodeId、ParentNodeId和NodeName三列的表格。对于每个节点,我想获取完整路径,例如“lvl1/lvl2/lvl3...”,其中lvl1、lvl2和lvl3是节点名称。我在此链接中找到了一个函数可以实现该功能:http://www.sql-server-helper.com/functions/get-tree-path.aspx,但我想使用CTE或其他技术来提高效率。请告知是否有更好的方法来实现此目标。谢谢。
declare @MyTable table (
NodeId int,
ParentNodeId int,
NodeName char(4)
)
insert into @MyTable
(NodeId, ParentNodeId, NodeName)
select 1, null, 'Lvl1' union all
select 2, 1, 'Lvl2' union all
select 3, 2, 'Lvl3'
declare @MyPath varchar(100)
;with cteLevels as (
select t.NodeId, t.ParentNodeId, t.NodeName, 1 as level
from @MyTable t
where t.ParentNodeId is null
union all
select t.NodeId, t.ParentNodeId, t.NodeName, c.level+1 as level
from @MyTable t
inner join cteLevels c
on t.ParentNodeId = c.NodeId
)
select @MyPath = case when @MyPath is null then NodeName else @MyPath + '/' + NodeName end
from cteLevels
order by level
select @MyPath
with cte (NodeId,NodeName,hierarchyPath)as
(
select NodeId,NodeName, NodeName
from Node
where ParentNodeId is null
union all
select n.NodeId, n.NodeName, CONVERT(varchar(256), cte.hierarchyPath + '/' + n.NodeName)
from Node n
join cte on n.ParentNodeId = cte.NodeId
)
select *
from cte
order by NodeId