如何在SQL中递归地自连接？

我有一张桌子：

Series ======== ID SeriesName ParentSeriesID 但这只返回第一级子节点，我想要父节点和所有下游节点。我不知道如何从这里取得进展

使用slq server 2005及以后版本中可用的CTE功能进行递归查询

USE AdventureWorks
GO
WITH Emp_CTE AS (
SELECT EmployeeID, ContactID, LoginID, ManagerID, Title, BirthDate
FROM HumanResources.Employee
WHERE ManagerID IS NULL
UNION ALL
SELECT e.EmployeeID, e.ContactID, e.LoginID, e.ManagerID, e.Title, e.BirthDate
FROM HumanResources.Employee e
INNER JOIN Emp_CTE ecte ON ecte.EmployeeID = e.ManagerID
)
SELECT *
FROM Emp_CTE
GO

您可以在此处查看示例：

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如果您使用的是SQL Server 2005+，则可以使用公共表表达式

With Family As 
( 
Select s.ID, s.ParentSeriesId, 0 as Depth
From Series s
Where ID = @ParentID 
Union All 
Select s2.ID, s2.ParentSeriesId, Depth + 1
From Series s2
    Join Family 
        On Family.ID = s2.ParentSeriesId 
) 
Select *
From Family 

更多信息：

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我只是加强了托马斯的工作。如果需要获取层次结构的深度并获取parentid，下面是代码

托马斯的作品也是如此

With Family As 
( 
    Select s.ID, s.ParentSeriesId, 0 as Depth
    From Series s
    Where ID = @ParentID <--- this was removed if you intend to get all hierarchy of the record. You can retain this if you want
  Union All 
     Select s2.ID, s2.ParentSeriesId < --- change to **Family.ParentID**, Depth + 1
     From Series s2
     Join Family 
         On Family.ID = s2.ParentSeriesId 
) 
 Select *
 From Family 

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就这些。我知道为时已晚，但我希望任何遇到这种情况的人都能帮助他们。感谢Thomas提供原始代码：

我修改了您的查询以使其正常工作，并将其放入我对您的问题的编辑中。谢谢你的帮助！有没有办法在非ms sql server数据库上执行此操作？“我需要一种更标准的方式而不使用CTE。@小悟空大师-取决于你的意思。同样的代码应该可以在Postgres、Oracle和DB2上正常工作。公共表表达式是SQL规范的一部分，因此由多个供应商实现。但是，听起来您在问如何在不支持CTE（如MySQL或MS Access）的数据库上实现同样的功能。答案将取决于product.cte=通用表表达式！

With Family As 
( 
    Select s.ID, s.ParentSeriesId, 0 as Depth
    From Series s
    Where ID = @ParentID <--- this was removed if you intend to get all hierarchy of the record. You can retain this if you want
  Union All 
     Select s2.ID, s2.ParentSeriesId < --- change to **Family.ParentID**, Depth + 1
     From Series s2
     Join Family 
         On Family.ID = s2.ParentSeriesId 
) 
 Select *
 From Family