3

给出表结构，如下所示：

ID ParentID 姓名
1 NULL A 根
2 NULL 另一个根
3 1 1 的孩子
4 3 1 的孙子
5 4 1 的曾孙
6 1 1 的孩子
7 NULL 另一个根
8 7 6 岁的孩子

我正在为单个 Sql 语句/函数寻找一个优雅（如果可能）的解决方案，当给定一个 Sql 语句/函数时，它将返回表中的所有数据ID = 1

所以我的结果看起来像：

ID ParentID 姓名
1 NULL A 根
3 1 1 的孩子
4 3 1 的孙子
5 4 1 的曾孙
6 1 1 的孩子

我在 SO 上看到过类似的问题，但在大多数情况下，他们似乎只关注给定数量的级别。

这种结构最终可以是无限的 - 与孩子一起文件夹，与许多其他孩子一起

这可能吗？如果是这样，我将如何实现它？

4

2 回答 2

3

所以参考这个答案：

SQL Server CTE 父子递归

这是您的架构的工作版本：

表创建脚本

CREATE TABLE YOUR_TABLE
    ([ID] int, [ParentID] int, [Name] varchar(21))
;
    
INSERT INTO YOUR_TABLE
    ([ID], [ParentID], [Name])
VALUES
    (1, NULL, 'A root'),
    (2, NULL, 'Another root'),
    (3, 1, 'Child of 1'),
    (4, 3, 'Grandchild of 1'),
    (5, 4, 'Great grandchild of 1'),
    (6, 1, 'Child of 1'),
    (7, NULL, 'Another root'),
    (8, 7, 'Child of 6')
;

递归 CTE

DECLARE @ID INT = 1

;WITH ParentChildCTE
AS (
    SELECT ID, ParentId, Name        
    FROM YOUR_TABLE
    WHERE Id = @ID

    UNION ALL

    SELECT T1.ID, T1.ParentId, T1.Name        
    FROM YOUR_TABLE T1
    INNER JOIN ParentChildCTE T ON T.ID = T1.ParentID
    WHERE T1.ParentID IS NOT NULL
    )
SELECT *
FROM ParentChildCTE

关键部分是在连接返回到结果集的CTE创建中，连接到，这不限制级别的数量。UNION ALLIDParentId

于 2014-08-28T14:22:20.723 回答
-1

您需要的是递归查询。此 Microsoft Technet 示例完全符合您的要求，但在示例中，我们将使用员工层次结构，而不是文件夹。

从链接页面：

-- Create an Employee table.
CREATE TABLE dbo.MyEmployees
(
EmployeeID smallint NOT NULL,
FirstName nvarchar(30)  NOT NULL,
LastName  nvarchar(40) NOT NULL,
Title nvarchar(50) NOT NULL,
DeptID smallint NOT NULL,
ManagerID int NULL,
 CONSTRAINT PK_EmployeeID PRIMARY KEY CLUSTERED (EmployeeID ASC) 
);
-- Populate the table with values.
INSERT INTO dbo.MyEmployees VALUES 
 (1, N'Ken', N'Sánchez', N'Chief Executive Officer',16,NULL)
,(273, N'Brian', N'Welcker', N'Vice President of Sales',3,1)
,(274, N'Stephen', N'Jiang', N'North American Sales Manager',3,273)
,(275, N'Michael', N'Blythe', N'Sales Representative',3,274)
,(276, N'Linda', N'Mitchell', N'Sales Representative',3,274)
,(285, N'Syed', N'Abbas', N'Pacific Sales Manager',3,273)
,(286, N'Lynn', N'Tsoflias', N'Sales Representative',3,285)
,(16,  N'David',N'Bradley', N'Marketing Manager', 4, 273)
,(23,  N'Mary', N'Gibson', N'Marketing Specialist', 4, 16);

接着

WITH DirectReports (ManagerID, EmployeeID, Title, DeptID, Level)
AS
(
-- Anchor member definition
    SELECT e.ManagerID, e.EmployeeID, e.Title, edh.DepartmentID, 
        0 AS Level
    FROM dbo.MyEmployees AS e
    INNER JOIN HumanResources.EmployeeDepartmentHistory AS edh
        ON e.EmployeeID = edh.BusinessEntityID AND edh.EndDate IS NULL
    WHERE ManagerID IS NULL
    UNION ALL
-- Recursive member definition
    SELECT e.ManagerID, e.EmployeeID, e.Title, edh.DepartmentID,
        Level + 1
    FROM dbo.MyEmployees AS e
    INNER JOIN HumanResources.EmployeeDepartmentHistory AS edh
        ON e.EmployeeID = edh.BusinessEntityID AND edh.EndDate IS NULL
    INNER JOIN DirectReports AS d
        ON e.ManagerID = d.EmployeeID
)
-- Statement that executes the CTE
SELECT ManagerID, EmployeeID, Title, DeptID, Level
FROM DirectReports
INNER JOIN HumanResources.Department AS dp
    ON DirectReports.DeptID = dp.DepartmentID
WHERE dp.GroupName = N'Sales and Marketing' OR Level = 0;
GO

你的结果是

ManagerID EmployeeID Title                         Level
--------- ---------- ----------------------------- ------
NULL      1          Chief Executive Officer       0
1         273        Vice President of Sales       1
273       16         Marketing Manager             2
273       274        North American Sales Manager  2
273       285        Pacific Sales Manager         2
16        23         Marketing Specialist          3
274       275        Sales Representative          3
274       276        Sales Representative          3
285       286        Sales Representative          3
于 2014-08-28T14:15:25.570 回答