mysql层次查询页面布局

CREATE TABLE employees (
    id INT PRIMARY KEY,
    name VARCHAR(100),
    manager_id INT,
    FOREIGN KEY (manager_id) REFERENCES employees(id)
);

WITH RECURSIVE employee_hierarchy AS (
    SELECT id, name, manager_id, 1 AS level
    FROM employees
    WHERE manager_id IS NULL
    UNION ALL
    SELECT e.id, e.name, e.manager_id, eh.level + 1
    FROM employees e
    INNER JOIN employee_hierarchy eh ON e.manager_id = eh.id
)
SELECT * FROM employee_hierarchy;

SELECT e1.id, e1.name, e2.name AS manager_name, e1.level
FROM (
    SELECT id, name, manager_id, 1 AS level
    FROM employees
    WHERE manager_id IS NULL
    UNION ALL
    SELECT e.id, e.name, e.manager_id, e2.level + 1
    FROM employees e
    INNER JOIN (
        SELECT id, name, manager_id, 1 AS level
        FROM employees
        WHERE manager_id IS NULL
    ) e2 ON e.manager_id = e2.id
) e1;