我的简单登录系统出错。 试图从数据库中读取

Question

I have this error "Warning: mysql_result(): user_id not found in MySQL result index 13 in C:\xampp\htdocs\core\functions\users.php on line 14"

I think i don't know how to read from my Database, it looks like

Here is my users code

<?php
    function user_exists($username){
            $username = sanitize($username);
            return (mysql_result(mysql_query("SELECT COUNT(`uID`) FROM `user` WHERE `uUserName` = '$username'"), 0) == 1) ? true : false;
    }

    function user_active($username){
            $username = sanitize($username);
            return (mysql_result(mysql_query("SELECT COUNT(`uID`) FROM `user` WHERE `uUserName` = '$username' AND `uActive` = 1"), 0) == 1) ? true : false;
    }

    function user_id_from_username($username){
            $username = sanitize($username);
            return mysql_result(mysql_query("SELECT `uID` FROM `user` WHERE `uUserName` = '$username'"), 0, 'user_id');
    }

    function login($username,$password){
            $user_id = user_id_from_username($username);

            $username = sanitize($username);
            $password = md5($password);

            return (mysql_result(mysql_query("SELECT COUNT(`uID`) FROM `user` WHERE `uUserName` = '$username' AND `uPassword` = '$password'"), 0) == 1) ? $user_id : false;
    }

?>

This is my login system code

if(empty($_POST) === false){
        $username = $_POST['username'];
        $password = $_POST['password'];

        if(empty($username) === true || empty($password) === true){
                $errors[] = 'You need to enter a Username and Password';
        } else if(user_exists($username) == false){
                $errors[] = 'We cannot find that Username, have you registered?';

        } else if(user_active($username) === false){
                $errors[] = 'You have not activated your account.';
        } 
        else {
                $login = login($username,$password);
                if($login === false){
                        $errors[] = 'The username or password is incorrect';
                } else {
                        echo 'ok';
                }
        }

        print_r($errors);

}

Answer 1

Currently the only problem that I see is your user_id_from_username function.

You're trying to set an offset to a field that doesn't exist and mysql doesn't find it. So it's throwing an error:

function user_id_from_username($username){
        $username = sanitize($username);
        return mysql_result(mysql_query("SELECT `uID` FROM `user` WHERE `uUserName` = '$username'"), 0, 'uID');
}

Try the above or leave off the uID since it's not a mandatory but rather an optional parameter.

Insert obligatory, you should be using mysqli instead of mysql at this point if your PHP version supports it.