多值进入数据库php，sql

Question

有人可以解释我如何修改此代码，这样我就可以插入多个值而不只是第一个。

 $aid = $_SESSION['assignmentid']; //Assignment id
  $query = "INSERT INTO studentgrade (studentid, assignmentid, studentpoints) values (:studentid, '$aid' , :studentpoints)";
  $query_params = array(':studentpoints' => $_POST['studentpoints'], ':studentid' => $_POST['studentid']);
  $points = null;
  $studentids = null;
  try
  {
     $carPrices = array_combine($_POST['studentpoints'], $_POST['studentid']);
      $stmt = $db->prepare($query);
      $stmt->bindParam(':studentid', $studentids);
      $stmt->bindParam(':studentpoints', $points);
     foreach ($carPrices as $points => $studentids) {

      $stmt->execute();
   }
  }
catch(PDOException $ex)
  {
    die("Error 1 " . $ex->getMessage());
  }

Answer 1

$aid = $_SESSION['assignmentid'];
$query = "INSERT INTO studentgrade (studentid, assignmentid, studentpoints) values ";
$carPrices = array_combine($_POST['studentpoints'], $_POST['studentid']);
$v = array();
foreach($carPrices as $a => $b) {
$v[] = "('$a', '$aid', '$b')";
}
$query .= implode(', ', $v);

$ query将＆＃34; INSERT INTO studentgrade（studentid，assignmentid，studentpoints）值（point1，aid，id1），（point2，aid，id2），[...＆＃34;