MySQL 计数返回 0

Question

如您所见，TotalPic 列返回 0。有什么问题？

SELECT P.*, U.*, COUNT(I.iid) AS TotalPic
FROM post P
LEFT JOIN users U ON U.uid = P.uid
LEFT JOIN images I ON I.pid = P.uid
WHERE P.pid = '2'

我尝试像这个线程解决方案一样使用 LEFT JOIN MYSQL COUNT return NULL? , 但还是一样。

+-----------+
|   images  |
+-----------+
| iid       |
| filename  |
| extension |
| pid       |
| uid       |
+-----------+

+-----------+
|   post    |
+-----------+
| pid       |
| uid       | 
|description|
| created_at|
+-----------+

+-----------+
|   users   |
+-----------+                
| uid   |
| fid       |
| date_reg  |
+-----------+

Answer 1

没关系，谢谢。我通过分离查询解决了它。我只需要计数，其他都无关紧要。

$result = mysql_query("
          SELECT COUNT(iid) AS total_photo 
          FROM images WHERE pid = '$pid'");