One of my friends told me that my validate.php file has some problems with SQL injections. Please feel free to [commit it on GitHub](https://github.com/poKe-Websites/poKe-Multimedia-editor/blob/master/admin/validate.php).

```
 <?php
 session_start();
 error_reporting(0);
 include("../config.php");
 $conn = new mysqli($hostname, $username, $password, $db_name);
 $query = mysqli_query($conn,"SELECT * FROM `Administrators` WHERE username = '"   . $_POST["usernamep"] . "' AND password='".  md5($_POST["passwordp"]) . "'");
if(mysqli_num_rows($query) > 0){
$_SESSION["username"] = $_POST["usernamep"];
header("Location: dashboard.php");
}else{
header("Location: index.php?alert");
}
?>

?>

```

Can you please try and improve my code to prevent SQL injections?