为什么我的代码返回此错误：mysql_query（）访问被拒绝用户''@ localhost'（使用密码no）

</div>
    <div class="items">
        <ul>
            <li>
            <?php echo $msg[$lang]["gtd"]; ?>
                <div class="text">
                    <strong>
                    <?php
                        $result = mysql_query("SELECT id FROM games WHERE `starttime` > ".(time()-86400));
                        echo mysql_num_rows($result);
                    ?></strong>
                </div>
            </li>

Line 8 of this code returns the error:

mysql_query() access denied for user ''@'localhost' (using password no)". 

https://stackoverflow.com/search?q=mysql_query%28%29+access+denied+for+user+%40%27localhost%27

This is an extremely popular issue on both SO, as well as Google.

You don't appear to have connected to the database at all. Include the following (populating the function arguments with your credentials, of course):

$connection = mysql_connect('localhost', 'db_username', 'db_password')
    or die('connection problem:' . mysql_error());

mysql_select_db('your_database', $connection);