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MySQL全文搜索多列未提供預期結果

[英]MySQL fulltext search over multiple columns does not deliver the expected results

我有一個名為“上載”的表格。 這些列是ID,日期,last_update,描述,標簽。 我添加了全文索引“ description_tags”,其中包括列說明和標簽。 表格式為MyISAM。 如果這可能是問題,我正在使用USBWebserver。

現在,我嘗試選擇其中具有提供的GET變量的上載。

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

但是結果的問題是:搜索“ lorem”時沒有結果,但是在查詢中添加IN BOOLEAN MODE時卻沒有結果。 “ Lorem”實際上位於描述列中。 在標簽列中搜索關鍵字沒有這個問題。 當我在描述表中搜索“ moree”時,甚至更有趣/煩惱,無論是否使用布爾模式,我都會得到結果...

這里有什么問題? 我沒看到

更新資料

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';

您的測試數據可能不完整。 請注意以下文檔

出現在50%或更多行中的單詞被認為是通用的,並且不匹配。

但是BOOLEAN MODE搜索的不同之處在於:

他們不使用50%閾值。

我猜“ lorem”出現在50%或更多的行中。

BOOLEAN MODE全文搜索不會通過降低相關性來自動排序。 您需要像這樣對它們自己進行排序:

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

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