Trouble with Recursive CTE in T-SQL for Hierarchical Data in SQL Server 2019
I keep running into I'm confused about I'm trying to retrieve a hierarchical structure from a table using a Recursive Common Table Expression (CTE) in SQL Server 2019, but I'm running into issues where the results don't match my expectations... The table `Employees` contains the following columns: `EmployeeID`, `ManagerID`, and `EmployeeName`. I want to display the hierarchy starting from a specific manager, for example, `ManagerID = 1`. I've written the following CTE: ```sql WITH EmployeeHierarchy AS ( SELECT EmployeeID, ManagerID, EmployeeName, 0 AS Level FROM Employees WHERE ManagerID = 1 UNION ALL SELECT e.EmployeeID, e.ManagerID, e.EmployeeName, eh.Level + 1 FROM Employees e INNER JOIN EmployeeHierarchy eh ON e.ManagerID = eh.EmployeeID ) SELECT * FROM EmployeeHierarchy; ``` However, when I run this query, I get results that include employees who do not report directly to the manager with `EmployeeID = 1`, and I can't figure out why. Additionally, the `Level` column seems to be incrementing correctly, but the results include some employees that should be filtered out. I've tried adjusting the initial `SELECT` statement to filter directly but it didn’t help. Also, I checked for any cyclic references in the data, but there shouldn’t be any. I'm getting unexpected output like: ``` | EmployeeID | ManagerID | EmployeeName | Level | |------------|-----------|---------------|-------| | 2 | 1 | John | 0 | | 3 | 1 | Alex | 0 | | 4 | 2 | Chris | 1 | | 5 | 3 | Sarah | 1 | | 6 | 4 | Tom | 2 | | 7 | 4 | Jerry | 2 | ``` I'm seeing employees with `ManagerID = 2` and `3` listed, but I expected them to be filtered out. Can anyone provide insights on what might be going wrong with my CTE implementation? Any advice would be much appreciated. This is part of a larger desktop app I'm building. Am I missing something obvious?