Php / PDO用户存在吗？

Question

I know there are already some posts about it, but I got other solution than others:

    $sql= 'SELECT * FROM pr_users WHERE nick = :nick ';
        $sqldot = $db->prepare($sql);
        $checkif = $sqldot->execute(array(':nick' => $nick));

        if (count($checkif) == 1) {
            $_SESSION['ng'] = "<p class=\"text-warning\">Nickname already exists!</p>";
            header("location: ../register.php");
        } else {
            $final++;
            $_SESSION['nick'] = $nick;
        }

$db is defined here:

$db = new PDO(
    "mysql:host=" .dbserver. ";dbname=" .dbname,dbuser,dbpass,
    array(
            PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8",
            PDO::MYSQL_ATTR_INIT_COMMAND => "SET CHARACTER SET utf8"
    )
  );

I count if $checkif has any characters in, but for some reason even if "name" does not exist -> $checkif still has some characters in, so it tells me that it already exist, which is wrong.

Answer 1

execute function Returns TRUE on success or FALSE on failure. Your if condition if (count($checkif) == 1) will be always true.

You need to fetch the results after execute() and check it count for results.

$checkif = $sqldot->execute(array(':nick' => $nick));
$result = $sqldot->fetch();
   if (!empty($result)) {
        $_SESSION['ng'] = "<p class=\"text-warning\">Nickname already exists!</p>";
        header("location: ../register.php");
    } else {
        $final++;
        $_SESSION['nick'] = $nick;
    }