MySQL 对多列的全文搜索没有提供预期的结果

Question

我有一个名为“上传”的表格。这些列是 id、date、last_update、description、tags。我添加了全文索引“description_tags”，其中包括那些列描述和标签。表格格式为 MyISAM。如果这可能是问题，我正在使用 USBWebserver。

现在我尝试选择其中包含提供的 GET 变量的上传。

MATCH (description,tags) AGAINST ("'.urldecode($_GET['tags']).'")

但是我得到的结果的问题是：当我搜索“lorem”时没有结果，但是当我在查询中添加 IN BOOLEAN MODE 时有一个结果。 “Lorem”实际上在描述列中。在标签列中搜索关键字没有这个问题。更有趣/更烦人的是，当我搜索同样在描述表中的“moree”时，我得到的结果有无布尔模式......

这里有什么问题？没看到。

更新

if ( $upload_display_sort == 'popular' )//sort by popularity

$query =    //select 'u' (a new defined variable?)
            'SELECT u.* '.
            //from the following table
            'FROM '.
            //uploads table as variable u
            'uploads u '.
            //join the following table
            'LEFT OUTER JOIN '.
            //select the column upload_id, count all columns into variable 'num' ???
            '(SELECT upload_id, COUNT(*) AS num '.
            //from the favorites table as variable f
            'FROM favorites f '.
            //and group it by the upload_id in the favorites table
            'GROUP BY upload_id) '.
            //what does this do? combine rows where the u.id == f.upload_id ???
            'f ON u.id = f.upload_id';

else $query = 'SELECT * FROM uploads';//select all from uploads



$query .=   ' WHERE online_state = 1';//select all online uploads



//FILTER FAVORITES

if  ($upload_display_sort == 'favorites' and !empty($favorites_ids))

$query .= ' AND id IN ('.implode(',', $favorites_ids).')';//returns 1,2,3,4,5

elseif  ($upload_display_sort == 'favorites' and empty($favorites_ids))

$query .= ' AND id IN (0)';//no upload id is 0



//FILTER SEARCH

if  (   isset($_GET['tags'])    )

$query .= ' AND MATCH (description,tags) AGAINST ("'.urldecode($_GET['tags']).'" IN BOOLEAN MODE)';



//FILTER DATE

if  (   isset($_GET['timeframe']    )

    and (   $_GET['timeframe'] == '3days'

        or  $_GET['timeframe'] == '2weeks'

        or  $_GET['timeframe'] == '3months')    )

{

    $end_date = time();//current time in unix format

    switch  (   $_GET['timeframe']  )

    {
        case '3days':   $start_date = strtotime('-3 days',$end_date);   break;
        case '2weeks':  $start_date = strtotime('-2 weeks',$end_date);  break;
        case '3months': $start_date = strtotime('-3 months',$end_date); break;
        default:        $start_date = strtotime('');    break;//1970-01-01 01:00:00
    }

    $end_date = date("Y-m-d H:i:s", $end_date);//current time in mysql format

    $start_date = date("Y-m-d H:i:s", $start_date);//end time in mysql format

    $query .= ' AND last_update BETWEEN "'.$start_date.'" AND "'.$end_date.'"';

}



//ORDER

$query .= ' ORDER BY';

if ( $upload_display_sort == 'popular' )//sort by popularity

$query .= ' f.num DESC,';

$query .= ' last_update DESC, id DESC';

Answer 1

您的测试数据可能不完整。请注意docs 中的以下内容：

考虑出现在 50% 或更多行中的单词 常见且不匹配。

然而BOOLEAN MODE searches 的不同之处在于：

他们不使用 50% 的阈值。

我猜“lorem”出现在 50% 或更多的行中。

BOOLEAN MODE 全文搜索不会通过降低相关性来自动排序。您需要像这样自己对它们进行排序：

SELECT *, MATCH (description,tags) AGAINST ("lorem") AS relevance
FROM uploads
WHERE MATCH (description,tags) AGAINST ("lorem" IN BOOLEAN MODE)
ORDER BY relevance DESC