如何通过基于分片ID的另一个表的计数来排序SQL查询的结果？

我有一个从数据库中提取帖子的SQL查询。一切工作正常，但现在我需要按每个帖子的评论数量排序结果。评论是在一个单独的表格上，他们有一个post_id列将其链接到该帖子。我需要根据评论表的数量来根据分片ID排序。我尝试了一切，但每次尝试添加一些内容到我的查询时，它都会停止运行并将我的页面留空。我需要帮助才能知道将其他JOIN语句放在哪里。这是我的查询：如何通过基于分片ID的另一个表的计数来排序SQL查询的结果？

$union = "UNION ALL 
       ( 
        SELECT DISTINCT wallposts.p_id,wallposts.is_profile_notes,wallposts.times_viewed,wallposts.columnTimesShared, 
        wallposts.marked,wallposts.secure_id,wallposts.reshared,wallposts.group_id, 
        wallposts.totaluploads,wallposts.WallUploadID,wallposts.type, 
        wallposts.value,wallposts.media,wallposts.youtube,wallposts.post_type, 
        wallposts.privacy,wallposts.tagedpersons,wallposts.with_friends_tagged,wallposts.emotion_head,wallposts.selected_emotion,wallposts.title, 
        wallposts.url,wallposts.description,wallposts.cur_image, 
        wallposts.uip,wallposts.likes,wallposts.userid, 
        wallposts.posted_by,wallposts.post as postdata,wallusers.*, 
        UNIX_TIMESTAMP() - wallposts.date_created AS TimeSpent, 

        PosterTable.mem_pic as posterPic, PosterTable.gender as posterGender,PosterTable.oauth_uid as poster_oauth_uid, PosterTable.username as posterUsername, 
        PosterTable.mem_fname as posterFname,PosterTable.work as posterWork, 
        PosterTable.mem_lname as posterLname,walllikes_track.id as PostLikeFound,wallposts.date_created 

        FROM 
         wallusers,wallusers as PosterTable, wallposts 
        LEFT JOIN walllikes_track 
         ON wallposts.p_id = walllikes_track.post_id AND walllikes_track.member_id = ".$user_id." 
        WHERE 
         wallusers.active = 1 
        AND 
         PosterTable.active = 1 
        AND 
         wallposts.group_id IN (".$groups.") 
        AND 
         wallposts.group_id != 0 
        AND 
         PosterTable.mem_id = wallposts.posted_by 
        AND 
         wallposts.marked < ".$this->flagNumber." 
        AND 
         wallusers.mem_id = wallposts.posted_by) ";

评论表被称为wallcomments，它有一个名为post_id的列。我知道我需要使用JOIN和COUNT，但我不知道把它放在我现在的代码中。

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2017-04-26 Romeo Hennessy

将一个额外的连接添加到子查询中，该子查询可以查找每个帖子的评论计数并使用它。我无法给出确切的答案，因为缺少很多细节，而且您的查询乱七八糟。 –

我应该在哪里插入JOIN？这是我的困境。每当我对查询进行任何更改时。它完全停止运行。 –

是的，因为你的查询非常庞大，难以理解，问题也是如此。下一次，通过展示您的问题的最小示例来提出更好的问题。没有人可以重现您现在的查询，因为甚至没有任何数据可用。 –

试试此查询，我没有运行，但我更新了它。

SELECT wallposts.p_id,wallposts.is_profile_notes,wallposts.times_viewed,wallposts.columnTimesShared, 
       wallposts.marked,wallposts.secure_id,wallposts.reshared,wallposts.group_id, 
       wallposts.totaluploads,wallposts.WallUploadID,wallposts.type, 
       wallposts.value,wallposts.media,wallposts.youtube,wallposts.post_type, 
       wallposts.privacy,wallposts.tagedpersons,wallposts.with_friends_tagged,wallposts.emotion_head,wallposts.selected_emotion,wallposts.title, 
       wallposts.url,wallposts.description,wallposts.cur_image, 
       wallposts.uip,wallposts.likes,wallposts.userid, 
       wallposts.posted_by,wallposts.post as postdata,wallusers.*, 
       UNIX_TIMESTAMP() - wallposts.date_created AS TimeSpent, 

       PosterTable.mem_pic as posterPic, PosterTable.gender as posterGender,PosterTable.oauth_uid as poster_oauth_uid, PosterTable.username as posterUsername, 
       PosterTable.mem_fname as posterFname,PosterTable.work as posterWork, 
       PosterTable.mem_lname as posterLname,walllikes_track.id as PostLikeFound,wallposts.date_created 

       FROM 
        wallusers,wallusers as PosterTable, wallposts 
       WHERE 
        wallusers.active = 1 
       AND 
        PosterTable.active = 1 
       AND 
        wallposts.group_id IN (".$groups.") 
       AND 
        wallposts.group_id != 0 
       AND 
        PosterTable.mem_id = wallposts.posted_by 
       AND 
        wallposts.marked < ".$this->flagNumber." 
       AND 
        wallusers.mem_id = wallposts.posted_by) " AND wallposts.p_id = walllikes_track.post_id AND walllikes_track.member_id = ".$user_id.";

来源

2017-04-26 06:23:27

谢谢您的回答，但您更新了哪部分？我没有看到任何改变。我没有看到引用评论表的任何内容。评论表称为wallcomments，它有一个名为post_id的列。 –

我删除了** UNION ALL ** ** JOIN **和** ON **关键字，因为SQL允许您在不使用JOIN的情况下连接表。例如， SELECT e.id，e.did，e.name，e.sal，d.department，FROM employee e，department d WHERE e.did = d.id： –

更可读的查询可能是这样的......

至少这样我们就会有机会。

SELECT DISTINCT p.p_id 
       , p.is_profile_notes 
       , p.times_viewed 
       , p.columnTimesShared 
       , p.marked 
       , p.secure_id 
       , p.media... 
      FROM wallposts p...

来源

2017-04-26 07:16:44 Strawberry

如何通过基于分片ID的另一个表的计数来排序SQL查询的结果？

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