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ステートメントの最後で HAVING 句を使用しているときに COUNT できない理由を理解するのに苦労しています。

このステートメントは次の結果を返します。

SELECT lid, cid, title, url, description, date, hits, downloadratingsummary, totalvotes, totalcomments, filesize, version, homepage, ns_compat, ns_des_img, ( (2.0 * (MATCH(title) AGAINST ('fsx concorde' IN BOOLEAN MODE))) + (1.0 * (MATCH(description) AGAINST ('fsx concorde' IN BOOLEAN MODE))) + (0.5 * (MATCH(url) AGAINST ('fsx concorde' IN BOOLEAN MODE))) ) AS relevance FROM nuke_downloads_downloads WHERE ( MATCH(title,description,url) AGAINST ('fsx concorde' IN BOOLEAN MODE) ) HAVING relevance > 3.0 ORDER BY relevance DESC

このステートメントは何も返しません

SELECT COUNT(*) as num, lid, cid, title, url, description, date, hits, downloadratingsummary, totalvotes, totalcomments, filesize, version, homepage, ns_compat, ns_des_img, ( (2.0 * (MATCH(title) AGAINST ('fsx concorde' IN BOOLEAN MODE))) + (1.0 * (MATCH(description) AGAINST ('fsx concorde' IN BOOLEAN MODE))) + (0.5 * (MATCH(url) AGAINST ('fsx concorde' IN BOOLEAN MODE))) ) AS relevance FROM nuke_downloads_downloads WHERE ( MATCH(title,description,url) AGAINST ('fsx concorde' IN BOOLEAN MODE) ) HAVING relevance > 3.0 ORDER BY relevance DESC

ここで何か不足していますか？

どうぞよろしくお願いいたします。

4

1 に答える 1

2

最初のクエリが返す行数だけが必要な場合は、クエリを派生テーブルにカプセル化できます。

リストの とrelevanceを除くすべての列をスキップできます。SELECTORDER BY

SELECT COUNT(*)
FROM
  ( SELECT ( (2.0 * (MATCH ... ) AS relevance 
    FROM ...                                     -- unchanged
    WHERE ...                                    -- unchanged
    HAVING relevance > 3.0
                                                 -- ORDER BY removed    
  ) AS t ;
于 2013-09-20T13:50:22.797 に答える