我的表tbl_posts
和tbl_comments
分别包含主键post_id
和comment_id
。我试过这段代码:
$allPosts=mysql_query("
select c.comment_id, post_id, count(*)
from post u,
comments c
where u.comment_id = c.comment_id
group by comment_id, post_id
LIMIT 10
");
但我不知道它的作用。如何组合两个表,以便总评论确定tbl_posts
列出的帖子的顺序?
答案 0 :(得分:1)
试试这个,如果你将每行分开并使用联接
,它会更具可读性select c.comment_id, post_id, count(*)
from post u join comments c
on u.comment_id = c.comment_id
group by comment_id, post_id LIMIT 10
答案 1 :(得分:1)
看起来您有名为 tbl_comment 和 tbl_post 的表格,但您的查询会将其列为评论并发布。
select c.comment_id, post_id, count(*)
from tbl_post u, tbl_comments c
where u.comment_id = c.comment_id
group by comment_id, post_id LIMIT 10
$allPosts=mysql_query("select c.comment_id, post_id, count(*) from tbl_post u, tbl_comments c where u.comment_id = c.comment_id group by comment_id, post_id LIMIT 10");
这只是修复了查询以便它运行,并且没有解决您可能遇到的任何内容问题,即两者上的分组(我猜的是主键)。
**编辑** 要修复排序,请尝试:
SELECT tbl_post.comment_id, count(*)
FROM tbl_post, tbl_comments
WHERE tbl_post.comment_id = tbl_comment.comment_id
GROUP BY comment_id LIMIT 10
ORDER BY count(*)
答案 2 :(得分:0)
SQL的解释:
您正在使用内部联接从表帖子中的表评论,列 post_id 中选择 comment_id 列,按 comment_id , post_id 进行分组,限制为10个结果。
我会尝试:
$allPosts = mysql_query("SELECT * FROM
(SELECT c.comment_id, u.post_id, COUNT(*) AS 'count' FROM post u
LEFT JOIN comments c ON c.comment_id = u.comment_id
GROUP BY c.comment_id, u.post_id)
ORDER BY count DESC LIMIT 10");