TSQL-映射父/子层次结构

如何解决TSQL-映射父/子层次结构

样本数据：

DECLARE @Hierarchy TABLE
    (
        [ParentId] INT,[ChildId]  INT
    ) ;

INSERT INTO @Hierarchy
VALUES
    ( 1,2 ),( 1,3 ),( 2,4 ),( 3,5 ),( 4,6 ),( 5,( 7,3 ) ;

当前查询：

; WITH CTE AS
    (
        SELECT  [ParentId],[ChildId],1 AS [Level],CONCAT ( CAST ( [ParentId] AS VARCHAR(MAX) ),'.',CAST ( [ChildId] AS VARCHAR(MAX) ) )  AS [Path]
        FROM    @Hierarchy
        UNION ALL
        SELECT  [C].[ParentId],[T].[ChildId],[C].[Level] + 1,CAST ( [C].[Path] + '.' + CAST([T].[ChildId] AS VARCHAR(MAX) ) AS VARCHAR(MAX) )
        FROM    CTE AS [C]
        JOIN    @Hierarchy AS [T]
        ON      [C].[ChildId] = [T].[ParentId]
    )
SELECT      *
FROM        CTE
ORDER BY    [ParentId],[Level],[ChildId] ;

目标：

1. 将共享“路径”的各个级别分组在一起
2. 找到共享“路径”的最浅层和最深层

预期输出：

注意：手动插入末尾带有橙色突出显示的记录以显示我的期望，但尚未弄清。

Group：基本上，遵循相同路径的每个节点“组”的“密集等级”。我认为，如果您查看上图中的Group值并将其与“ Level and Path”字段的数据相关联，那将会更有意义。

IsShallowest：第一级（现在有人举起我可以看到它）。只需弄清楚如何导出那些丢失（重复）的记录

IsDeepest：组中的最高级别。

一旦确定了“组”逻辑并添加丢失（重复）的记录，就很容易弄清楚IsShallowest和IsDeepest。

解决方法

请检查此解决方案。它提供了所需的解决方案，除了添加了需要更多信息的额外行

;WITH CTE AS (
    SELECT  
        [ParentId],[ChildId],1 AS [Level],CONCAT ( CAST ( [ParentId] AS VARCHAR(MAX) ),'.',CAST ( [ChildId] AS VARCHAR(MAX) ) )  AS [Path],MyGroup1 = ROW_NUMBER() OVER(ORDER BY [ParentId]),MyGroup2 = ROW_NUMBER() OVER(ORDER BY [ParentId])
    FROM Hierarchy
    UNION ALL
    SELECT  
        [C].[ParentId],[T].[ChildId],[C].[Level] + 1,CAST ( [C].[Path] + '.' + CAST([T].[ChildId] AS VARCHAR(MAX) ) AS VARCHAR(MAX) ),MyGroup1 = C.MyGroup1,MyGroup2 = [C].[MyGroup1] + ROW_NUMBER() OVER(ORDER BY [T].[ParentId]) - 1
    FROM CTE AS [C]
    JOIN Hierarchy AS [T] ON [C].[ChildId] = [T].[ParentId]
),MyCTE2 as (
    SELECT
        [ParentId],[Level],[Path]
        -- un-comment bellow 2 rows to see the logic
        --,MyGroup1
        --,MyGroup2,MyGroup = DENSE_RANK() OVER (ORDER BY MyGroup1,MyGroup2)
    FROM CTE
),MyCTE3 as (
    SELECT
        [ParentId],[Path],MyGroup,shallowest = ROW_NUMBER() OVER(PARTITION BY MyGroup ORDER BY [Path]),deepest = ROW_NUMBER() OVER(PARTITION BY MyGroup ORDER BY [Path] DESC) 
    FROM MyCTE2
)
SELECT
    [ParentId],ISshallowest = CASE WHEN shallowest = 1 then 1 else 0 END,Isdeepest = CASE WHEN deepest = 1 then 1 else 0 END
FROM MyCTE3
ORDER BY
    --[Path]
    [ParentId],[ChildId];