使用SqlServer CTE递归查询处理树、图和层次结构

 WITH CTE AS
 (
   SELECT EmpId, ReportTo, FName FROM Employ WHERE EmpId=
   UNION ALL
   SELECT emp.EmpId, emp.ReportTo, emp.FName FROM CTE JOIN Employ as emp ON CTE.EmpId=emp.ReportTo
 )

 USE AdventureWorks;
 GO
 --Creates an infinite loop
 WITH cte (EmployeeID, ManagerID, Title) as
 (
   SELECT EmployeeID, ManagerID, Title
   FROM HumanResources.Employee
   WHERE ManagerID IS NOT NULL
  UNION ALL
   SELECT cte.EmployeeID, cte.ManagerID, cte.Title
   FROM cte 
   JOIN HumanResources.Employee AS e 
     ON cte.ManagerID = e.EmployeeID
 )
 --Uses MAXRECURSION to limit the recursive levels to 
 SELECT EmployeeID, ManagerID, Title
 FROM cte
 OPTION (MAXRECURSION );
 GO