变量数与php的参数数量不匹配

Question

Just begun to learn php and encounter this problem.: mysqli_stmt::bind_param(): Number of variables doesn't match number of parameters in prepared statement

Everything is working, my data is saved to database, and i get the message that show, "Registration successful", but i still get that error message.

Error is shown in this line

$stmt->bind_param("ssss", $firstname, $surname, $passwor, $email);

$firstname = $_POST['firstname'];
$surname = $_POST['surname'];
$passwor = $_POST['passwor'];
$email = $_POST['email'];

if (!empty($firstname) || !empty($surname) || !empty($passwor) || !empty($email))
  {
    $host = "localhost";
    $dbusername = "root";
    $dbpassword = "";
    $dbname = "registration";

    $conn = new mysqli ($host, $dbusername, $dbpassword, $dbname);
    if (mysqli_connect_error())
      {
       die ('Connect Error(' . mysqli_connect_errno().')'. mysqli_connect_error());
      }
    else
      {
        $SELECT = "SELECT email From loginas Where email = ? Limit 1";
        $INSERT = "INSERT Into loginas (`firstname`, `surname`, `passwor`, `email`) values('$firstname', '$surname', '$passwor', '$email')";

        $stmt = $conn->prepare($SELECT);
        $stmt->bind_param("s", $email);
        $stmt->execute();
        $stmt->bind_result($email);
        $stmt->store_result();
        $rnum = $stmt->num_rows;

        if ($rnum==0)
          {
            $stmt->close();

            $stmt = $conn->prepare($INSERT);
            $stmt->bind_param("ssss", $firstname, $surname, $passwor, $email);
            $stmt->execute();
            echo "Registartion sucesfull";
          }  
        else
          {
            echo "This email is already in use";    
          }
          $stmt->close();
          $conn->close();
      }
  }
else {
     echo "All fields must be filled";
     die();
  }

Answer 1

You are preparing this statement later in yor code and passing bound parameter so it needs to be written with a ? for each parameter you are binding to it

$INSERT = "INSERT Into loginas 
                (`firstname`, `surname`, `passwor`, `email`) 
            values(?,?,?,?)";