如何通过MySQL＆amp;检查电子邮件是否是唯一的PHP？

Question

所有

我想检查用户提交的电子邮件是否已存在于我的数据库中。我挣扎着代码（多年来没有写任何东西）：

    //Assign variables based on the form submitted
    $name = $_POST['name'];
    $email = $_POST['email'];
    $newsletter = $_POST['newsletter'];

    //check if email is unique
    $query = "SELECT SELECT * FROM Members WHERE member_email='$email'";
    $result = mysql_query($query);

    if($result)
    {       
        //Generate password function above
    }
    else
    {
        //Do something
    }

它经常说电子邮件已经注册，尽管情况并非如此。

会感激一些指点！

谢谢！

EDIT ---------------

出现此错误：

    Warning: mysql_num_rows() expects parameter 1 to be resource, boolean given in /var/sites/g/site/public_html/Registered.php on line 25

来自编辑过的代码：

    //check if email is unique
    $query = "SELECT SELECT * Members WHERE member_email='$email'";
    $result = mysql_num_rows(mysql_query($query));

    if($result == 0)
    {       
          //Do something
    }
    else
    {
          //Duplicate
    }