how to establish sql connection in php code example

Example 1: php sql 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.";
?>

Example 2: mysql connection phpmyadmin

<?php
  // This is for checking if your file is linked in your page or game or whatever
  echo "IT WORKS"; // My File is successfuly Linked

  //Remember to create a Database in phpmyadmin or any Online Database
  // the values passed in this parameters are:  the host, the user, user password and the database Name
  $con = mysqli_connect('localhost', 'root', 'root', 'unityaccess');

  // check that connection happen
  if(mysqli_connect_errno()) {
    echo "1: Connection Failed"; //error code #1 = connection Failed
    exit();
  }
?>