可捕获的致命错误:类PDOStatement的对象无法转换为字符串

Question

尝试将数据库上的值与表单中传递的值匹配以检查用户是否存在时,我收到以下错误.

可捕获的致命错误:类PDOStatement的对象无法转换为字符串

这是我正在使用的代码:

//Check users login details
    function match_login($username, $password){
            //If the button has been clicked get the variables
            try{

                $dbh = new PDO("mysql:host=localhost;dbname=mjbox","root", "usbw");

            } catch( PDOException $e ) {

                echo $e->getMessage();

            }
            $stmt = $dbh->prepare("SELECT * FROM mjbox WHERE username=? AND password=?");
            $stmt->bindParam(1, $username);
            $stmt->bindParam(2, $password);
            $stmt->execute();

            $result = mysql_query($stmt);
            if( mysql_num_rows($result) > 0 ){

                echo 'There is a match!';
            }else{
                echo 'nooooo';
            }
    }

Answer 1

mysql_query()和PDO不兼容,不能一起使用.您正在尝试传递mysql_query()期望字符串的PDO语句对象.相反,您希望$stmt通过PDO的一个提取方法获取行,或者检查返回的行数rowCount():

$stmt = $dbh->prepare("SELECT * FROM mjbox WHERE username=? AND password=?");
$stmt->bindParam(1, $username);
$stmt->bindParam(2, $password);

if ($stmt->execute()) {

  // get the rowcount
  $numrows = $stmt->rowCount();
  if ($numrows > 0) {
    // match
    // Fetch rows
    $rowset = $stmt->fetchAll();
  }
  else {
    // no rows
  }
}