MySQL 8.0 - Unexpected 'No data' when using CTE with Recursive Query for Hierarchical Data
I'm stuck trying to I'm stuck trying to I'm currently working with MySQL 8.0, trying to leverage Common Table Expressions (CTE) for retrieving hierarchical data from my employee table. I have set up a recursive query to fetch all subordinates under a given manager, but I keep getting 'No data' returned even when I know there are matching rows. Here’s the structure of my employee table: ```sql CREATE TABLE employees ( id INT PRIMARY KEY, name VARCHAR(100), manager_id INT, FOREIGN KEY (manager_id) REFERENCES employees(id) ); ``` I’m using the following recursive CTE: ```sql WITH RECURSIVE subordinates AS ( SELECT id, name, manager_id FROM employees WHERE manager_id = ? UNION ALL SELECT e.id, e.name, e.manager_id FROM employees e INNER JOIN subordinates s ON e.manager_id = s.id ) SELECT * FROM subordinates; ``` When I run this query with the manager_id set to a valid ID, it returns an empty result set. I have double-checked that there are indeed records in the database that should match the criteria, but it seems the recursive part isn’t functioning correctly. I have also tried running the initial SELECT query separately to ensure it retrieves data: ```sql SELECT id, name FROM employees WHERE manager_id = ?; ``` This returns the expected results. After some debugging, I noticed that if I replace the `INNER JOIN` with a `LEFT JOIN`, I still get 'No data'. I’ve also played around with the hierarchy depth, but that hasn’t helped either. Could anyone point out what might be going wrong with my recursive CTE? Are there certain configurations or settings in MySQL 8.0 that I need to be aware of for recursion to work correctly? Any insights would be greatly appreciated! I'm using Sql 3.9 in this project. I'd really appreciate any guidance on this. For context: I'm using Sql on Ubuntu 20.04.