SQL Server: implementing CTE recursion depth exceeding allowed limit in hierarchical queries
Hey everyone, I'm running into an issue that's driving me crazy. I tried several approaches but none seem to work. I'm working with an scenario when trying to execute a recursive Common Table Expression (CTE) in SQL Server 2019. The CTE is designed to retrieve hierarchical data from an employee table that includes a self-referencing foreign key for manager relationships. However, when the hierarchy is deep, I receive the behavior: `Msg 50000, Level 16, State 1, Line 10 Recursive CTE exceeded the maximum recursion limit of '100'`. I've attempted to adjust the recursion limit using `OPTION (MAXRECURSION n)` but it still fails for deeper hierarchies. Here's the CTE I'm working with: ```sql WITH EmployeeHierarchy AS ( SELECT EmployeeID, ManagerID, Name, 0 AS Level FROM Employees WHERE ManagerID IS NULL -- Start with top-level managers 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; ``` I initially thought that increasing the recursion limit might help, so I tried: ```sql WITH EmployeeHierarchy AS ( SELECT EmployeeID, ManagerID, Name, 0 AS Level FROM Employees WHERE ManagerID IS NULL 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 OPTION (MAXRECURSION 500); -- Attempting to increase the recursion limit ``` This still resulted in the same behavior. I've verified the data and it seems like there's no cyclic reference in the employee hierarchy. I've also tried optimizing the query by filtering down the dataset before the recursive call, but the scenario continues. Any suggestions on how to address this question or alternative approaches to fetch the hierarchical data efficiently? What am I doing wrong? My development environment is macOS. Am I missing something obvious?