php mysql connection

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

// Create connection
$conn= mysqli_connect($servername,$username,$password,$dbname);
// Check connection
if (!$conn) {
  die("Connection failed: " . mysqli_connect_error());
}
echo "Connected Successfully.";
?>

$servername = "localhost";
$username = "username";
$password = "password";

// Create connection
$conn = new mysqli($servername, $username, $password);

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


Simplified

$conn = mysqli_connect('localhost', 'username', 'password');
$database = mysqli_select_db($conn, 'database');

<?php

$con = mysqli_connect("localhost","my_user","my_password","my_db");

 
// Check connection

 if (mysqli_connect_errno()) {

  echo "Failed to connect to MySQL: " . mysqli_connect_error();

    
  exit();
}

?>
 

<?php
$servername = "localhost";
$username = "username";
$password = "password";

// Create connection
$conn = new mysqli($servername, $username, $password);

 
// Check connection

 if ($conn->connect_error) {

  die("Connection failed: " . $conn->connect_error);
}

echo "Connected successfully";

?>