如何获取自引用表中每条记录的所有子项

Question

我的表格如下：

ID   | ChildsID | Name         
-----------------------              
1       NULL       Name1
2       1          Name2
3       2          Name3
4       3          Name4
5       4          Name5
6       5          Name6
7       6          Name7
8       7          Name8
9       8          Name9
10      9          Name10
11      3          Name11

现在，我需要一个查询，该查询可以为每个至少有一个子记录的记录获取所有可能的子记录，并返回如下数据集：

ID   | ParentID |   Name   |   ParentIDs         
-----------------------------------------              
1       NULL       Name1       11,10,9,8,7,6,5,4,3,2
2       1          Name2       11,10,9,8,7,6,5,4,3
3       2          Name3       11,10,9,8,7,6,5,4
4       3          Name4       10,9,8,7,6,5
5       4          Name5       10,9,8,7,6
6       5          Name6       10,9,8,7
7       6          Name7       10,9,8
8       7          Name8       10,9
9       8          Name9       10

Answer 1

您可以尝试使用此选项：

  SELECT a.*,x.ParentIDs
    FROM YourTable a
    CROSS APPLY (SELECT STUFF(CAST((SELECT ',' + CONVERT(VARCHAR,b.ID) 
    FROM YourTable b WHERE b.ID > a.ID AND ISNULL(b.ParentID,0) > ISNULL(a.ParentID,0) ORDER BY ID DESC
    FOR XML PATH(''), TYPE) AS VARCHAR(MAX)),1,1,'') AS ParentIDs ) x
    WHERE x.ParentIDs IS NOT NULL

Answer 2

使用此查询。

更新结果：Fiddler演示

    CREATE TABLE TABLE1 (ID INT, ParentID INT, NAME VARCHAR(10));
INSERT INTO TABLE1 VALUES(1, NULL, 'Name1');
INSERT INTO TABLE1 VALUES(2, 1, 'Name2');
INSERT INTO TABLE1 VALUES(3, 2, 'Name3');
INSERT INTO TABLE1 VALUES(4, 3, 'Name4');
INSERT INTO TABLE1 VALUES(5, 4, 'Name5');
INSERT INTO TABLE1 VALUES(6, 5, 'Name6');
INSERT INTO TABLE1 VALUES(7, 6, 'Name7');
INSERT INTO TABLE1 VALUES(8, 7, 'Name8');
INSERT INTO TABLE1 VALUES(9, 8, 'Name9');
INSERT INTO TABLE1 VALUES(10, 9, 'Name10');
INSERT INTO TABLE1 VALUES(11, 3, 'Name11');

  SELECT ID, ParentID , Name, Child = STUFF((
          SELECT ',' + CAST(B.ID AS VARCHAR(100)) FROm TABLE1 AS B 
          WHERE ISNULL(A.ID, 0) < B.ID AND B.ID NOT IN(
              ISNULL((SELECT TOP 1 C.ID FROm TABLE1 AS C 
                      WHERE C.ParentID IN (
                            SELECT ParentID FROM TABLE1 WHERE ID <= A.ID) 
                      ORDER BY C.ID DESC), 0))  
          ORDER BY B.ID DESC 
          FOR XML PATH (''), type).value('.', 'varchar(max)'), 1,1,'')
 FROm TABLE1 AS A

旧结果：

 SELECT ID, ParentID , Name, ParentIDs = STUFF((
  SELECT ',' + CAST(B.ID AS VARCHAR(100)) FROm MyTable AS B 
  WHERE ISNULL(A.ID, 0) < B.ID ORDER BY B.ID  DESC FOR XML PATH (''), type).value('.',
          'varchar(max)'), 1,1,'')
 FROm MyTable AS A