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SQL中基于行ID合并列的问题

sql mariadb

SQL中基于行ID合并列的问题,sql,pivot,mariadb,group-concat,nested-queries,Sql,Pivot,Mariadb,Group Concat,Nested Queries,我需要根据列名为ID的行合并comment列，以便将对已评论帖子的回复合并到已回复帖子的计数值，即comment\u counts。我需要在新闻提要的单个线程中显示嵌套注释。下面是我的SQL查询 SELECT DISTINCT ft.ID as ID, ft.userid, ft.content, ft.timestamp, ft.comments as comment_counts, ftc.comment, ftc.timestamp as comment_timestamp, uq.use

我需要根据列名为
ID
的行合并
comment
列，以便将对已评论帖子的回复合并到已回复帖子的计数值，即
comment\u counts
。我需要在新闻提要的单个线程中显示嵌套注释。
下面是我的SQL查询

SELECT DISTINCT ft.ID as ID, ft.userid, ft.content, ft.timestamp, ft.comments as comment_counts, ftc.comment, ftc.timestamp as comment_timestamp, uq.username, uq.avatar 
FROM users uq, feed_item ft 
LEFT JOIN feed_item_comment ftc ON ftc.postid = ft.ID 
LEFT JOIN user_friends uf ON uf.friendid = ftc.userid 
LEFT JOIN users u ON u.ID = uf.friendid WHERE uq.ID = ft.userid AND ft.userid
IN 
(SELECT u.ID FROM users u WHERE u.ID 
    IN (SELECT uf.friendid FROM user_friends uf WHERE uf.status = '2' AND uf.userid = '".$this->user->info->ID."') 
        OR 
        u.ID 
        IN (SELECT uf.userid FROM user_friends uf WHERE uf.status = '2' AND uf.friendid = '".$this->user->info->ID."') 
        OR
        u.ID = '".$this->user->info->ID."'
) ORDER BY ft.ID DESC, ftc.timestamp DESC

实际结果：

这是从上述查询中获得的结果

ID  userid      content                 timestamp   comment_counts  comment         comment_timestamp       username        avatar   
___________________________________________________________________________________________________________________________________________

3   1           This is manju           13:12:31        2           manju comment   13:17:31                manju           1698862132.png   
3   1           This is manju           13:12:31        2           new cmt         14:00:15                manju           1698862132.png   
2   14          How are you doing?      13:06:42        2           Fine            15:00:15                Nishanth        default.png   
2   14          How are you doing?      13:06:42        2           Not Good        15:05:10                Nishanth        default.png   
1   14          How are you?            14:07:00        2           Look Good       20:00:00                Nishanth        default.png   
1   14          How are you?            14:07:00        2           So I'm!         20:10:00                Nishanth        default.png
对于包含多条注释的单个新闻提要帖子，在包含嵌套注释的单独提要中显示。 尽管嵌套注释重复显示。但是有单独的新闻提要线程

预期结果：

ID  userid  content             timestamp   comment_counts  comment1        comment1_timestamp  comment2    comment2_timestamp  username    avatar   
_______________________________________________________________________________________________________________________________________________________

3   1       This is manju       13:12:31        2           manju comment   13:17:31            new cmt     14:00:15            manju       1698862132.png   
2   14      How are you doing?  13:06:42        2           Fine            15:00:15            Not Good    15:05:10            Nishanth    default.png   
1   14      How are you?        14:07:00        2           Look Good       20:00:00            So I'm!     20:10:00            Nishanth    default.png
我只需要以一条新闻帖子作为一个线程显示嵌套评论（不重复）
例如，对于带有消息“您好”的单个新闻提要，正如我用“好”和“不好”评论的那样
“你好”一文重复了两遍。因为我已经用文本“好”和“不好”评论了两次
我需要如何防止嵌套注释在单个新闻提要中作为线程重复两次

使用
GROUP_CONCAT（ftc.comment）作为回复

ID userid   content         timestamp     comment_counts   comment      comment_timestamp   username   avatar           replies  
__________________________________________________________________________________________________________________________________________________________________________

1   14      How are you?    14:07:00            2           Look Good   20:00:00            Nishanth   default.png   Look Good,Fine,Not Good,manju comment,new cmt,Look...
使用查询完成数据库： 使用
GROUP\u CONCAT（ftc.comment）
作为回复

ID userid   content         timestamp     comment_counts   comment      comment_timestamp   username   avatar           replies  
__________________________________________________________________________________________________________________________________________________________________________

1   14      How are you?    14:07:00            2           Look Good   20:00:00            Nishanth   default.png   Look Good,Fine,Not Good,manju comment,new cmt,Look...
我应该如何编写SQL查询，以便从获得的结果中合并行，以获得所需/预期的结果？

尝试下面使用row_number（）和条件聚合

您可能需要阅读数据透视表。虽然您想要做的不是典型的pivot，但您仍然在尝试将行转换为列，pivot就是这么做的。您的mysql版本@nishanthMariaDB服务器版本是什么：10.1.36@fa06I感谢您的努力。查询运行得非常好。但是回复的动态值和帖子的时间戳，即评论计数>2。既然我已经附加了（7，2，14，'你的努力还不错！'，'08:13:10'，0，0，0），我该如何处理你的问题呢；对于发布的
内容
值=
你做得怎么样？
从
提要项目
表中，将
注释作为回复值=
不好
添加到
表中。
从
提要项目
表中，它应该作为动态回复的一部分显示在下一列的后面这篇评论文章。从而自动创建一个新的栏来回复帖子。威尔，你能帮我吗@尼桑斯ॐ, 你能把它加到你的预期输出吗？请稍等minute@Nishanthॐ maria db您的版本支持pivot吗？

select id, userid,content,timestamp,comment_count,
min(case when seq=1 then comment end) as comment1,
min(case when seq=1 then comment_timestamp end) as commenttime1,
min(case when seq=2 then comment end) as comment2,
min(case when seq=2 then comment_timestamp end) as commenttime2
from
(
select *,row_number() over(partition by id,userid order by comment_timestamp) as seq from 
(SELECT DISTINCT ft.ID as ID, ft.userid, ft.content, ft.timestamp, ft.comments as comment_count, ftc.comment, ftc.timestamp as comment_timestamp, uq.username, uq.avatar FROM users uq,
feed_item ft 
LEFT JOIN feed_item_comment ftc ON ftc.postid = ft.ID
LEFT JOIN user_friends uf ON uf.friendid = ftc.userid 
LEFT JOIN users u ON u.ID = uf.friendid WHERE uq.ID = ft.userid AND ft.userid
IN 
(SELECT u.ID FROM users u WHERE u.ID 
IN (SELECT uf.friendid FROM user_friends uf WHERE uf.status = '2' AND uf.userid = 1) 
OR u.ID IN 
(SELECT uf.userid FROM user_friends uf WHERE uf.status = '2' AND uf.friendid = 1) 
OR
u.ID = 1
)ORDER BY ft.ID DESC, ftc.timestamp DESC)X)Y
group by id, userid,content,timestamp,comment_count