识别表中后续的父子层次结构

Question

我在表中有父子关系。我想使用父子关系表填充一个新表，该表将包含子级和层次结构中的所有后续父级。

我一直在研究所提供的解决方案，但无法编写能够为我提供所需结果的查询。

以下代码可用于创建表和加载示例数据

create table DemoTable
(
    accountid bigint
    ,parentid bigint
    ,accountname nvarchar(128)
)
insert DemoTable(accountid,parentid,accountname)
select 1, null, 'Root'
union select 2, 1, 'Child1'
union select 3, 1, 'Child2'
union select 4, 1, 'Child3'
union select 5, 2, 'Child1.1'
union select 6, 2, 'Child1.2'
union select 7, 3, 'Child1.3'
union select 8, 7, 'Child1.3.7'
go

输出应该如下所示

accountid    parentid    hierarchyLevel
8    7    3
8    3    2
8    1    1
7    3    2
7    1    1
3    1    1
6    2    2
6    1    1
2    1    1

Answer 1

这可能会有所帮助....

DECLARE  @DemoTable table
(
    accountid bigint
    ,parentid bigint
    ,accountname nvarchar(128)
)
insert  @DemoTable(accountid,parentid,accountname)
select 1, null,    'Root'
union select 2, 1, 'Child1'
union select 3, 1, 'Child2'
union select 4, 1, 'Child3'
union select 5, 2, 'Child1.1'
union select 6, 2, 'Child1.2'
union select 7, 3, 'Child1.3'
union select 8, 7, 'Child1.3.7'

;WITH CTE
AS
(
SELECT accountid,parentid--,LEN(REPLACE(REPLACE(accountname,'.',''),'Child','')) hierarchyLevel
FROM @DemoTable
WHERE accountname <> 'Root'

UNION ALL

SELECT c.accountid ,d.parentid--,LEN(REPLACE(REPLACE(accountname,'.',''),'Child','')) hierarchyLevel
FROM @DemoTable d 
INNER JOIN CTE c ON d.accountid = c.parentid
WHERE d.accountname <> 'Root'

)
SELECT *,ROW_NUMBER() OVER( PARTITION  BY accountid  ORDER BY accountid ASC ,parentid ASC) hierarchyLevel
FROM CTE
order by accountid DESC ,parentid DESC --, CAST(hierarchyLevel as INT) DESC
option (maxrecursion 0)

Answer 2

我们可以使用Common Table Expression (CTE)来解决这个问题。

首先，我们将使用递归 CTE 将每个孩子带到他们的父母身边。最初，我们将每个孩子的标签表示为 1。然后，我们递归地增加他们父母的数字。

因此，父母的标签价值会更高，而孩子的标签价值会更少。

然后我们通过使用accountId按照label值的降序进行分区得到行号（因为叶子的标签值更高）

通过这样做，我们得到了预期的数据。然后我们做了一些排序，以与问题中显示的预期输出相同的方式显示它。

代码如下和here is the live dbfiddle

create table DemoTable
(
    accountid bigint
    ,parentid bigint
    ,accountname nvarchar(128)
)
insert DemoTable(accountid,parentid,accountname)
select 1, null, 'Root'
union select 2, 1, 'Child1'
union select 3, 1, 'Child2'
union select 4, 1, 'Child3'
union select 5, 2, 'Child1.1'
union select 6, 2, 'Child1.2'
union select 7, 3, 'Child1.3'
union select 8, 7, 'Child1.3.7'
go

;WITH ChildParentHierarchy AS
(
    SELECT accountId, parentId, 1 AS label
    FROM DemoTable WHERE parentid IS NOT NULL

    UNION ALL

    SELECT cte.accountId, D.parentId, (cte.label + 1) AS label
    FROM DemoTable D
    INNER JOIN ChildParentHierarchy cte
    ON D.accountid = cte.parentid
    WHERE D.parentid IS NOT NULL
)

SELECT
    accountId, 
    parentId, 
    ROW_NUMBER() OVER (
        Partition BY accountId 
        ORDER BY label DESC
    ) AS hierarchyLevel
INTO #temp --we are storing the value of CTE
FROM ChildParentHierarchy
ORDER BY accountid DESC

--final result
SELECT * FROM #temp
ORDER BY accountid DESC, hierarchyLevel DESC

DROP TABLE #temp

希望对您有所帮助，谢谢！

Answer 3

您可以尝试此解决方案（根据您的架构更改字段名称）：

  WITH CTE AS (
      SELECT accountid, ParentId,0 AS [Level], CAST(accountid AS varchar(1000)) AS Heirarchy,accountid AS TopParentId
      FROM dbo.DemoTable
      WHERE accountid IN (SELECT accountid FROM DemoTable WHERE ParentId IS NULL)
      UNION ALL

      SELECT mgr.accountid, mgr.ParentId, CTE.[Level] +1 AS [Level], 
            CAST(( CAST(mgr.accountid AS VARCHAR(1000)) + '>' + CTE.Heirarchy) AS varchar(1000)) AS Heirarchy, CTE.TopParentId
      FROM CTE
        INNER JOIN dbo.DemoTable AS mgr
          ON CTE.accountid = mgr.ParentId
    )
    select  * from cte order by heirarchy desc

编辑
这里加入了层次结构，得到每个id的层次关系。这并不完全是需要的，但可能会有所帮助。