php - 如何根据分片 ID 按另一个表的计数对 SQL 查询的结果进行排序？

Question

我有一个从数据库获取帖子的 SQL 查询。一切正常，但现在我需要根据每个帖子的评论数量对结果进行排序。评论位于单独的表中，并且有一个 post_id 列将其链接到帖子。我需要根据分片 ID 按评论表的数量对帖子进行排序吗？我已经尝试了一切，但每次我尝试向查询中添加某些内容时，它都会完全停止运行并将页面留空。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:

    $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，但我不知道将其放在当前代码中的何处。

Answer 1

尝试这个查询，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.";