Connect to MySQL database via the mysqli command

mysqli-connection

<?php
$mysqli = mysqli_connect('host', 'username', 'password', 'database');
if (mysqli_connect_errno($mysqli)) {
  echo "Failed to connect to MySQL: " . mysqli_connect_error();
}

$res = mysqli_query($mysqli, "SELECT id FROM tablename");
$row = mysqli_fetch_assoc($res);

while ($row = $res->fetch_assoc()) {
  echo 'id = ' . $row['id'] . "\n";
}

#  Reset the internal result pointer
// $res->data_seek(0);
  
// http://php.net/manual/en/book.mysqli.php  
 ?>