Ainur Shakirov

if(mysqli_num_rows(mysqli_query($conn, 'SELECT * FROM userst WHERE email='.$_POST['email']))==0)

if(mysqli_num_rows(mysqli_query($conn, 'SELECT * FROM userst WHERE email="'.$_POST['email'].'"'))==0)

"SELECT * FROM " . parent::PREFIX . $this->table . " WHERE from_user = 3 OR to_user = 3 ORDER BY date ASC";