How can a login system with multiple users and MySQL be implemented in PHP?

To implement a login system with multiple users and MySQL in PHP, you can create a users table in your MySQL database to store user credentials. When a user tries to log in, you can query the database to check if the provided username and password match any records in the users table. If a match is found, you can create a session for that user to keep them logged in. 

<?php
// Database connection
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";

$conn = new mysqli($servername, $username, $password, $dbname);

// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

// Login form submission
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $username = $_POST['username'];
    $password = $_POST['password'];

    $sql = "SELECT * FROM users WHERE username='$username' AND password='$password'";
    $result = $conn->query($sql);

    if ($result->num_rows == 1) {
        // Start session and redirect to dashboard
        session_start();
        $_SESSION['username'] = $username;
        header("Location: dashboard.php");
    } else {
        echo "Invalid username or password";
    }
}

$conn->close();
?>

Keywords

PHP MySQL login system multiple users implementation

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