SQLite: Unexpected Behavior with PRAGMA Foreign Keys and Recursive Queries
I'm learning this framework and I'm migrating some code and I've been struggling with this for a few days now and could really use some help... I'm working with SQLite version 3.35.5 and encountering an unexpected behavior when using `PRAGMA foreign_keys = ON` in conjunction with recursive queries. I have two tables, `employees` and `departments`, where each employee has a `department_id` that references the `departments` table. My goal is to generate a list of all employees along with their department names, but I'm also trying to include those departments in a hierarchical format. Here's the schema for my tables: ```sql CREATE TABLE departments ( id INTEGER PRIMARY KEY, name TEXT NOT NULL, parent_id INTEGER, FOREIGN KEY (parent_id) REFERENCES departments(id) ); CREATE TABLE employees ( id INTEGER PRIMARY KEY, name TEXT NOT NULL, department_id INTEGER, FOREIGN KEY (department_id) REFERENCES departments(id) ); ``` I inserted some test data like this: ```sql INSERT INTO departments (id, name, parent_id) VALUES (1, 'Corporate', NULL); INSERT INTO departments (id, name, parent_id) VALUES (2, 'Sales', 1); INSERT INTO departments (id, name, parent_id) VALUES (3, 'Support', 1); INSERT INTO employees (id, name, department_id) VALUES (1, 'Alice', 2); INSERT INTO employees (id, name, department_id) VALUES (2, 'Bob', 3); INSERT INTO employees (id, name, department_id) VALUES (3, 'Charlie', 2); ``` When I run the following recursive query to get a list of departments and their employees, I’m not seeing the expected results: ```sql WITH RECURSIVE department_hierarchy AS ( SELECT id, name, parent_id FROM departments WHERE parent_id IS NULL UNION ALL SELECT d.id, d.name, d.parent_id FROM departments d INNER JOIN department_hierarchy dh ON dh.id = d.parent_id ) SELECT dh.name AS department, e.name AS employee FROM department_hierarchy dh LEFT JOIN employees e ON dh.id = e.department_id; ``` I expect to see each employee listed under their respective department, but instead, I'm getting `NULL` values for the `employee` column when there are no employees in that department, which is correct. However, the problem arises when I have departments that do not have a single employee assigned but should still appear in the result set. I’ve tried adjusting my query using `LEFT JOIN` but still got unexpected results. Any suggestions on how to correctly implement this query while ensuring that all departments are included, even those without employees? I also want to ensure that foreign key constraints are being respected properly. For context: I'm using Sql on Windows. Has anyone else encountered this? I'm using Sql stable in this project. What's the best practice here? I've been using Sql for about a year now. What would be the recommended way to handle this? This is my first time working with Sql LTS. What would be the recommended way to handle this?