Mysql 如何处理这个复杂的查询?

Mysql 如何处理这个复杂的查询?,mysql,sql,database,Mysql,Sql,Database,这是我的数据库架构: Post: id title body date Tag: id title Post_Tag: id id_post id_tag Comment: id id_post body date 这是一个查询,用于显示包含所有相关标记和评论编号的帖子 SELECT p.ID, p.title, p.body, p.c_date, GROUP_CONCAT(DISTINCT CONCAT_WS('|', CAST(t.ID AS

这是我的数据库架构:

Post:
id
title
body
date

Tag:
id
title

Post_Tag:
id
id_post
id_tag

Comment:
id
id_post
body
date
这是一个查询,用于显示包含所有相关标记和评论编号的帖子

SELECT
    p.ID,
    p.title,
    p.body,
    p.c_date,
    GROUP_CONCAT(DISTINCT CONCAT_WS('|', CAST(t.ID AS CHAR), t.title) SEPARATOR ';') AS tags,
    COUNT(c.ID) AS comments
FROM Post p
    LEFT JOIN Comment c ON p.ID = c.id_post
    LEFT JOIN Post_Tag pt ON p.ID = pt.id_post
    LEFT JOIN Tag t ON pt.id_tag = t.ID
GROUP BY p.ID, p.title, p.body, p.c_date
ORDER BY p.c_date DESC
问题是评论的编号错误

如果帖子有3个标签,有1条评论,那么它会告诉我有3条评论,而不仅仅是1条

因此,它向我显示(注释编号)*(关联标签编号)注释

如何解决此问题?

使用
计数(不同的c.ID)
而不是
计数(c.ID)

使用
计数(不同的c.ID)
代替
计数(c.ID)

COUNT(DISTINCT c.ID)AS comments
有效吗?
COUNT(DISTINCT c.ID)AS comments
有效吗?
SELECT
    p.ID,
    p.title,
    p.body,
    p.c_date,
    GROUP_CONCAT(DISTINCT CONCAT_WS('|', 
                                    CAST(t.ID AS CHAR), 
                                    t.title) SEPARATOR ';') AS tags,
    COUNT(DISTINCT c.ID) AS comments
FROM Post p
    LEFT JOIN Comment  AS c  ON p.ID      = c.id_post
    LEFT JOIN Post_Tag AS pt ON p.ID      = pt.id_post
    LEFT JOIN Tag      AS  t ON pt.id_tag = t.ID
GROUP BY p.ID, 
         p.title, 
         p.body, 
         p.c_date;
ORDER BY p.c_date DESC