Question

出于某种原因，我将帖子表与评论混合在一起....所以这是comment_of=0的帖子和comment_of= (number of a post)的评论

帖子

 id_post | id_poster | comment_of | post 
  23          3            0         hi       
  24          4            0        hello     
  25          5            0         how are you      
  26          3            25        lets go      
  27          3            24        come on      
  28          4            25        haha       
  29          3            25        go away  
  30          2            24        aint funny  
  31          3            23        lol  
  32          3            0         ok  
  35          3            0         here we go

现在我想要的是按照它有comments.comment_of的数量订购帖子。 DESC。

MySql 像这样的东西

  SELECT post 
  FROM posts
  WHERE comment_of=0
  ORDER BY (number of `comment of`) DESC

我期待的是这样的事情

  id_post | id_poster | comment_of | post 
  25          5            0         hi  (3 comments)      
  24          4            0         hello  (2 comments)   
  23          3            0         how are you (1 comment)      
  32          3            0         ok          (0 comments) 
  35          3            0         here we go  (0 comments)

Answer 1

您可以在order by中使用子查询：

SELECT p.post 
FROM posts p
WHERE p.comment_of = 0
ORDER BY (SELECT COUNT(*) FROM posts p2 WHERE p2.comment_of = p.id_post) DESC;

Answer 2

您可以LEFT JOIN在同一个表格和id_post上进行SELECT p.*, count(p2.id_post) as num from posts p left join posts p2 on p2.comment_of = p.id_post where p.comment_of = 0 group by p.id_post order by num desc;，并获取计数：

+---------+-----------+------------+--------------+-----+
| id_post | id_poster | comment_of | post         | num |
+---------+-----------+------------+--------------+-----+
|      25 |         5 |          0 | how are you  |   3 |
|      24 |         4 |          0 | hello        |   2 |
|      23 |         3 |          0 | hi           |   1 |
|      35 |         3 |          0 | here we go   |   0 |
|      32 |         3 |          0 | ok           |   0 |
+---------+-----------+------------+--------------+-----+

输出：

sqlqry1 = "INSERT INTO Timesheet ([StrEMPId]) VALUES (" & TmpEmpId & ");"

按表sql的注释数量排序

2 个答案: