php - PHP の with insert

Question

$m = clearData($_POST['msg']);
$sql = "INSERT INTO messages(message,message_from)
  VALUES('$m','$_SESSION['id']')";

挿入時にエラーが発生し、見つかりません:

Parse error: syntax error, unexpected T_ENCAPSED_AND_WHITESPACE, expecting T_STRING or T_VARIABLE or T_NUM_STRING