private $username;
private $password;
protected function Login(){
    $user = hash('sha256', $this->username);
    $pass = hash('sha256', $this->password);
    $this query = "..."
    ...
}

$searchstring = explode(' ', $search);
//.... Some lines of PHP code... and the resulting query is: ...
$this->query = "SELECT... WHERE name LIKE 'DELETE%' OR name LIKE 'FROM%' ";
$this->query.= " OR name LIKE 'USERS%' OR name LIKE 'WHERE%' OR name LIKE '1%'";

$query= mysqli_real_escape_string($database_connection, $user)

$query = mysqli_real_escape_string($database_connection, trim($user))

function mssql_escape($data) {
    if(is_numeric($data))
        return $data;
    $unpacked = unpack('H*hex', $data);
    return '0x' . $unpacked['hex'];
}