multiple queries in node js

const mysql = require('mysql');

const connection = mysql.createConnection({
  host: 'localhost',
  user: 'yourusername',
  password: 'yourpassword',
  database: 'yourdatabase'
});

connection.connect((err) => {
  if (err) throw err;
  console.log('Connected to MySQL database');

  // First query
  connection.query('SELECT * FROM users', (err, results) => {
    if (err) throw err;
    console.log('First query results:', results);

    // Second query
    connection.query('SELECT * FROM products', (err, results) => {
      if (err) throw err;
      console.log('Second query results:', results);

      // Third query
      connection.query('SELECT * FROM orders', (err, results) => {
        if (err) throw err;
        console.log('Third query results:', results);

        // Close the connection
        connection.end((err) => {
          if (err) throw err;
          console.log('MySQL connection closed');
        });
      });
    });
  });
});

Explanation: 1. Import MySQL Module: Require the mysql module in your Node.js application to work with MySQL databases. 2. Create Connection: Create a connection to the MySQL database using the createConnection method and provide necessary connection details like host, username, password, and database name. 3. Connect to Database: Use the connect method to establish a connection to the MySQL database. Handle any connection errors that might occur. 4. First Query: Execute a SELECT * FROM users query. Upon success, log the results to the console. 5. Second Query: Perform another query SELECT * FROM products. Handle any errors and log the results. 6. Third Query: Execute a SELECT * FROM orders query. Handle errors and log the results. 7. Close Connection: Use the end method to gracefully close the MySQL connection. Handle any potential errors while closing the connection.

This code demonstrates how to perform multiple queries sequentially in Node.js using the mysql module and handle each query's results and errors.