node mysql树形递归

CREATE TABLE employees (
    id INT PRIMARY KEY,
    name VARCHAR(255),
    parent_id INT
);

const mysql = require('mysql');

const connection = mysql.createConnection({
    host: 'localhost',
    user: 'your_username',
    password: 'your_password',
    database: 'your_database'
});

connection.connect();

function getTree(id) {
    return new Promise((resolve, reject) => {
        connection.query('SELECT * FROM employees WHERE id = ?', [id], (error, results) => {
            if (error) return reject(error);
            const employee = results[0];
            if (!employee) return resolve(null);

            getSubordinates(employee.id).then(subordinates => {
                employee.subordinates = subordinates;
                resolve(employee);
            }).catch(reject);
        });
    });
}

function getSubordinates(parentId) {
    return new Promise((resolve, reject) => {
        connection.query('SELECT * FROM employees WHERE parent_id = ?', [parentId], (error, results) => {
            if (error) return reject(error);
            const promises = results.map(subordinate => getTree(subordinate.id));
            Promise.all(promises).then(resolve).catch(reject);
        });
    });
}

getTree(1).then(tree => {
    console.log(JSON.stringify(tree, null, 2));
}).catch(error => {
    console.error(error);
});

connection.end();