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如何获得每篇帖子的最新评论？分组时显示第一条评论记录[关闭]

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SELECT * FROM（ comments ）LEFT JOIN posts ON posts . id = comments . case_id WHERE comments . user_id = '8' GROUP BY comments . case_id ORDER BY comments . created_date DESC我的编码就是这个 . 如何获得每篇帖子的最新评论？同时将其分组显示第一条评论记录

php mysql sql database codeigniter

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    SELECT *
FROM (  SELECT comments.*
        FROM comments 
        INNER JOIN comment2article USING (comment_id)
        WHERE comment2article.article_d= ID_of_article
    ) MAIN_TABLE 
LEFT JOIN ( SELECT comments.*
            FROM comments 
            INNER JOIN comment2article USING (comment_id)
            WHERE comment2article.article_d= ID_of_article
        ) DUMMY_TABLE ON (MAIN_TABLE.comment_id = DUMMY_TABLE.comment_id AND MAIN_TABLE.created < DUMMY_TABLE.created)
WHERE DUMMY_TABLE.comment_id IS NULL;

    尝试以上查询 .

    希望这会帮助你 .

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