Ich habe eine Oracle CONNECT BY-Anweisung in SQL Server 2008 erfolgreich simuliert, indem ich diese beiden vorherigen Antworten befolgt habeHie undHie und anpassen, um die Ergebnisse zu erhalten, die ich brauche. Aber wie mache ich das in LINQ?

Hier ist ein Beispiel für die Verwendung einer Dummy-Datenbank:

CREATE TABLE Employee(
 EmployeeID INT IDENTITY(1,1) PRIMARY KEY,
 Department INT NOT NULL,
 EmployeeName VARCHAR(40) NOT NULL,
 PeckingOrder INT NOT NULL,
 HigherDepartment INT NULL)

INSERT INTO Employee (Department,EmployeeName,PeckingOrder,HigherDepartment)
VALUES (1,'Bart',1,NULL),(2,'Homer',1,1),(2,'Marge',2,NULL),
       (3,'Lisa',1,2),(3,'Maggie',2,2),(3,'Santas Helper',3,1)

EmployeeID Department EmployeeName PeckingOrder HigherDepartment
    1            1     Bart            1             NULL
    2            2     Homer           1              1 
    3            2     Marge           2             NULL
    4            3     Lisa            1              2
    5            3     Maggie          2              2
    6            3     Santas Helper   3              1

und dies ist der SQL-Code, mit dem die Erbe zurückgegeben wird:

WITH n(level, PeckingOrder, Department, EmployeeName, HigherDepartment) AS 
    (SELECT 1, PeckingOrder, Department, EmployeeName, HigherDepartment
    FROM Test.dbo.Employee
    WHERE Department = 3
        UNION ALL
   SELECT n.level + 1, nplus1.PeckingOrder, nplus1.Department, nplus1.EmployeeName, nplus1.HigherDepartment 
   FROM Test.dbo.Employee as nplus1
   JOIN n ON n.HigherDepartment = nplus1.Department)
SELECT MAX(level) AS level, PeckingOrder, Department, EmployeeName, HigherDepartment   
FROM n
GROUP BY PeckingOrder, Department, EmployeeName, HigherDepartment
ORDER BY MAX(level) DESC, PeckingOrder ASC

level PeckingOrder Department EmployeeName HigherDepartment
  3         1           1           Bart             NULL
  2         1           2           Homer              1
  2         2           2           Marge             NULL
  1         1           3           Lisa               2
  1         2           3           Maggie             2
  1         3           3           Santas Helper      1