SQL Server: Issue with Recursive CTE Not Returning Expected Results for Hierarchical Data
I'm working through a tutorial and I keep running into I'm stuck trying to I've been banging my head against this for hours. I'm working with SQL Server 2019 and trying to retrieve hierarchical data using a recursive Common Table Expression (CTE). However, I'm not getting the expected results when I attempt to traverse the hierarchy. My data consists of a simple employee table structured as follows: ```sql CREATE TABLE Employees ( EmployeeID INT PRIMARY KEY, ManagerID INT, Name NVARCHAR(100) ); INSERT INTO Employees (EmployeeID, ManagerID, Name) VALUES (1, NULL, 'Alice'), (2, 1, 'Bob'), (3, 1, 'Charlie'), (4, 2, 'David'), (5, 2, 'Eve'), (6, 3, 'Frank'); ``` I want to retrieve the hierarchy starting from 'Alice' (EmployeeID = 1) and include all levels down to the leaf nodes. Here's my CTE: ```sql WITH EmployeeHierarchy AS ( SELECT EmployeeID, ManagerID, Name, 0 AS Level FROM Employees WHERE EmployeeID = 1 UNION ALL SELECT e.EmployeeID, e.ManagerID, e.Name, Level + 1 FROM Employees e INNER JOIN EmployeeHierarchy eh ON e.ManagerID = eh.EmployeeID ) SELECT * FROM EmployeeHierarchy; ``` When I run this query, I only get 'Alice' in the result set, and it seems that the recursion isn't pulling in the child records as expected. I've verified that the data is correct, and I even tried adding a termination condition using a maximum level, but it didn't help. Is there something I'm missing in the CTE definition? I've also checked for circular references in the data, but everything looks fine. Any insights into what could be causing this behavior would be greatly appreciated. This is part of a larger CLI tool I'm building. I'd really appreciate any guidance on this. Any advice would be much appreciated. This is part of a larger CLI tool I'm building. What are your experiences with this? Am I approaching this the right way?