PHP统计论坛帖子

Question

我正在努力计算帖子数量 在“帖子”表中，

i have id,topic_id (topic_id= the topic id)

在“主题”表中，

i have id,f_id (f_id= the forum id )

我一边尝试，一边尝试，但不是 我怎么能算上这些帖子？ 例如：

<php?
$test2=mysql_query("SELECT *, COUNT(topic_id) AS post_count FROM posts t LEFT JOIN topics p ON p.id = t.id WHERE `f_id`='1' GROUP BY t.id") or die (mysql_error());
?>

Answer 1

尝试此查询：

SELECT *, COUNT(topic_id) AS post_count 
FROM posts t 
LEFT JOIN topics p 
ON p.id = t.id AND `f_id`='1' 
GROUP BY t.id