Retrieve data from a table || Get value from database php

<?php

$con=mysqli_connect("localhost","admin","abc123","mydb");

// Check connection

if (mysqli_connect_errno())

  {

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

  }

$result = mysqli_query($con,"SELECT * FROM users");

while($row = mysqli_fetch_array($result))

  {

  $display = $row['firstname'];

  echo"$display";

  }

  

mysqli_close($con);

?>