php - 在查询中使用 "ORDER BY count"时出错

Question

我正在使用以下查询来显示一些信息:

$result = mysqli_query ($con,"SELECT * FROM files,members,member_group WHERE files.member_id = members.member_id AND members.member_id = member_group.member_id AND group_id='$id' ORDER BY count DESC ");

我的问题是当我省略 ORDER BY count DESC 时它工作正常但是当它在那里时我收到以下错误:

Warning: mysqli_fetch_array() expects parameter 1 to be mysqli_result, boolean given in /proj/co600/project/repo/public_html/select_field3.php on line 227

Count 是我数据库中的一列，它记录了出版物被下载的次数。

Answer 1

count 是一个聚合函数，所以你需要用反引号把它括起来。

要清楚地了解您的错误..您需要像这样更改您的代码..

$result = mysqli_query ($con,"SELECT * FROM files,members,member_group WHERE files.member_id = members.member_id AND members.member_id = member_group.member_id AND group_id='$id' ORDER BY count DESC ");
if(!$result)
{
 die(mysqli_error($con));
}