MySQL COUNT返回0

时间:2012-07-27 01:41:42

标签: mysql count

正如您在此处所见,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'

我尝试使用LEFT JOIN这样的线程解决方案MYSQL COUNT return NULL?,但仍然相同。

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

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

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

1 个答案:

答案 0 :(得分:0)

没关系,谢谢。我通过分离查询解决了它。我只需要数量,否则无所谓。

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