SQL Server 实现递归获取层级数据

经常会出现一个业务场景，当前已知ID，怎么获取他的子节点数据呢？怎么获取父节点的数据呢？下面用代码展示一个最简单的例子：

/*创建一张员工表*/
CREATE TABLE [dbo].[Employee](
    [ID] [uniqueidentifier] NOT NULL,--用户ID
    [ParentGUID] [uniqueidentifier] NOT NULL,--上级ID
    [ECode] [nvarchar](50) NOT NULL,--员工编号
    [EName] [nvarchar](200) NOT NULL--员工名称
 CONSTRAINT [PK_Employee] PRIMARY KEY CLUSTERED 
(
    [ID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]

/*插入几条基础数据*/

INSERT [dbo].[Employee] ([ID], [ParentGUID], [ECode], [EName]) VALUES (N'CF06903A-1D9B-4896-916E-56E4B8CB1955', N'00000000-0000-0000-0000-000000000000', N'SG001', N'董事长')
INSERT [dbo].[Employee] ([ID], [ParentGUID], [ECode], [EName]) VALUES (N'DD994FDA-1703-4616-AF1B-165164DF710E', N'CF06903A-1D9B-4896-916E-56E4B8CB1955', N'SG0012', N'经理')
INSERT [dbo].[Employee] ([ID], [ParentGUID], [ECode], [EName]) VALUES (N'138C93C0-387B-4582-8A56-E036056A97F2', N'DD994FDA-1703-4616-AF1B-165164DF710E', N'SG0013', N'部长')
INSERT [dbo].[Employee] ([ID], [ParentGUID], [ECode], [EName]) VALUES (N'88F1D9F7-CC02-4449-BA0A-8717142FFB4D', N'138C93C0-387B-4582-8A56-E036056A97F2', N'SG0014', N'主管')
INSERT [dbo].[Employee] ([ID], [ParentGUID], [ECode], [EName]) VALUES (N'166FA95A-0425-40E3-8CB9-2A4C97CA4CC6', N'88F1D9F7-CC02-4449-BA0A-8717142FFB4D', N'SG00141', N'邵工')
INSERT [dbo].[Employee] ([ID], [ParentGUID], [ECode], [EName]) VALUES (N'6E94AA52-700A-4415-BB8A-34345605E13D', N'88F1D9F7-CC02-4449-BA0A-8717142FFB4D', N'SG00142', N'李工')
INSERT [dbo].[Employee] ([ID], [ParentGUID], [ECode], [EName]) VALUES (N'C5E537D4-0994-43E2-A1AB-3F736B4E22D3', N'88F1D9F7-CC02-4449-BA0A-8717142FFB4D', N'SG00143', N'高工')
INSERT [dbo].[Employee] ([ID], [ParentGUID], [ECode], [EName]) VALUES (N'61F79EAF-DB86-425E-A61C-4228265EEC28', N'88F1D9F7-CC02-4449-BA0A-8717142FFB4D', N'SG00144', N'卜工')
INSERT [dbo].[Employee] ([ID], [ParentGUID], [ECode], [EName]) VALUES (N'34C26725-3726-4C45-90C0-440C91EF34B8', N'88F1D9F7-CC02-4449-BA0A-8717142FFB4D', N'SG00145', N'苏工')

　　

/*获得主管所有上司*/
;WITH cteTemp AS
(
	SELECT [ID], [ParentGUID], [ECode], [EName]
	FROM [Employee] WHERE ID = '88F1D9F7-CC02-4449-BA0A-8717142FFB4D'/*主管ID*/
	UNION ALL
	SELECT A.[ID], A.[ParentGUID], A.[ECode], A.[EName]
	FROM [Employee] A 
	INNER JOIN cteTemp B ON A.[ID] = B.[ParentGUID]
)
SELECT *  FROM cteTemp

　　

/*获得主管所有手下*/
;WITH cteTemp AS
(
	SELECT [ID], [ParentGUID], [ECode], [EName]
	FROM [Employee] WHERE ID = '88F1D9F7-CC02-4449-BA0A-8717142FFB4D'/*主管ID*/
	UNION ALL
	SELECT A.[ID], A.[ParentGUID], A.[ECode], A.[EName]
	FROM [Employee] A 
	INNER JOIN cteTemp B ON A.[ParentGUID] = B.[ID]
)
SELECT *  FROM cteTemp