php - 具有不同价值观的问题

Question

我在这里有一些 php 代码，应该显示来自名为“集合”的字段的唯一/不同值。我已成功连接到其他地方的数据库。当这个 php 代码执行时，浏览器会给我一个“警告：mysql_fetch_array()：提供的参数不是第 20 行 mypage.php 中的有效 MySQL 结果资源”

         $id = isset($_GET['id'])?(int)$_GET['id']:0; // if $_GET['id'] exists, return it as an integer, otherwise use a sentinel, id's usually start with 1, so 0 works

       if ($id!=0): 
// I assume this is a specific news item meaning you know it's ONE result
$query = 'SELECT * DISTINCT (Collections) FROM Audios LIMIT 40'; // so try to use limit     1, no need to add extra steps in the database lookup
    else: 
$query = 'SELECT * DISTINCT (Collections) FROM Audios ORDER BY Collections DESC LIMIT 40'; 
    endif;

   $result = mysql_query($query);
;
// now loop through the results ***(This is Line 20)***
while ($row = mysql_fetch_array($result)){
// and use'em however you wish
echo '

 <div>

  <li><a href="#">'.$row['Collections'].'</a></p>
</div>
 '; 
   }

Answer 1

SELECT  DISTINCT (Collections) FROM Audios ORDER BY Collections DESC LIMIT 40

删除两个查询中的 *。