PHP MySQLi mysqli_connect_error()

mysqli_connect_error()

The mysqli_connect_error() function returns the error description from the last connection if one exists.

EXAMPLE

<?php
$server = "localhost";
$username = "root";
$password = "wrong_password"; // INTENTIONAL ERROR: The default password in XAMPP is empty ""
$database = "mysqli_database";

// Attempting connection
$connection = mysqli_connect($server, $username, $password, $database);

// Check if an error description exists
// NOTE: Since we entered the wrong password, the function mysqli_connect_error() 
// will detect the issue and, instead of a number, will output the full text 
// of the error reported by the MySQL server (Access denied...).
if (mysqli_connect_error()) {
    echo "An error occurred while connecting: " . mysqli_connect_error();
} else {
    echo "Connection was established without errors.";
}

mysqli_close($connection);
?>

RESULT

The result will be displayed here...

Practical use: This function is indispensable during development, as it displays the exact reason why the connection failed in the browser. Test it at home like this:

If the connection succeeds, the function returns NULL.

The displayed text is usually in English, as returned by the MySQL server.

In production (on a live website), it is best not to display these errors to visitors for security reasons.