TSQL遞歸更新？

Question

我不知道是否存在於TSQL（CTE）遞歸更新

ID parentID value 
-- -------- ----- 
1 NULL  0 
2 1  0 
3 2  0 
4 3  0 
5 4  0 
6 5  0 

我能夠更新列value遞歸使用e.g CTE從ID = 6至最頂部行？

Answer 1

是的，應該是。 MSDN gives an example：

USE AdventureWorks; 
GO 
WITH DirectReports(EmployeeID, NewVacationHours, EmployeeLevel) 
AS 
(SELECT e.EmployeeID, e.VacationHours, 1 
    FROM HumanResources.Employee AS e 
    WHERE e.ManagerID = 12 
    UNION ALL 
    SELECT e.EmployeeID, e.VacationHours, EmployeeLevel + 1 
    FROM HumanResources.Employee as e 
    JOIN DirectReports AS d ON e.ManagerID = d.EmployeeID 
) 
UPDATE HumanResources.Employee 
SET VacationHours = VacationHours * 1.25 
FROM HumanResources.Employee AS e 
JOIN DirectReports AS d ON e.EmployeeID = d.EmployeeID;