MySQL查询 - 选择的所有帖子和计数为每一个

Question

评论这是我国上午3点30，所以我需要睡觉，但我不能没有这样的：

我试图让所有帖子（使用Zend_Db）并为每个人评论。

模式

blog_posts：

+---------------+------------------+------+-----+---------+----------------+ 
| Field   | Type    | Null | Key | Default | Extra   | 
+---------------+------------------+------+-----+---------+----------------+ 
| id   | int(10) unsigned | NO | PRI | NULL | auto_increment | 
| title   | varchar(255)  | NO |  | NULL |    | 
| content  | text    | NO |  | NULL |    | 
| alias   | varchar(100)  | NO |  | NULL |    | 
| user_id  | int(11)   | NO |  | NULL |    | 
| created_date | datetime   | NO |  | NULL |    | 
| modified_date | datetime   | YES |  | NULL |    | 
| thumbnail  | varchar(255)  | YES |  | NULL |    | 
+---------------+------------------+------+-----+---------+----------------+ 

而这里的blog_comments：

+---------------+------------------+------+-----+---------+----------------+ 
| Field   | Type    | Null | Key | Default | Extra   | 
+---------------+------------------+------+-----+---------+----------------+ 
| id   | int(10) unsigned | NO | PRI | NULL | auto_increment | 
| user_id  | int(11)   | NO |  | NULL |    | 
| post_id  | int(11)   | NO |  | NULL |    | 
| comment  | text    | NO |  | NULL |    | 
| created_date | datetime   | NO |  | NULL |    | 
| modified_date | datetime   | YES |  | NULL |    | 
+---------------+------------------+------+-----+---------+----------------+ 

注：blog_comments.post_id与blog_posts.id联系。

---

我想一个生成的表像：

+---------------+------------------+------+-----+---------+----------------+ 
| Field   | Type    | Null | Key | Default | Extra   | 
+---------------+------------------+------+-----+---------+----------------+ 
| id   | int(10) unsigned | NO | PRI | NULL | auto_increment | 
| title   | varchar(255)  | NO |  | NULL |    | 
| content  | text    | NO |  | NULL |    | 
| alias   | varchar(100)  | NO |  | NULL |    | 
| user_id  | int(11)   | NO |  | NULL |    | 
| created_date | datetime   | NO |  | NULL |    | 
| modified_date | datetime   | YES |  | NULL |    | 
| thumbnail  | varchar(255)  | YES |  | NULL |    | 
+---------------+------------------+------+-----+---------+----------------+ 
| TEMPOROARY COLUMN IN OBJECT ($post->comment)        | 
+---------------+------------------+------+-----+---------+----------------+ 
| comments  |     |  |  |   |    | 
+---------------+------------------+------+-----+---------+----------------+ 

---

现在，这里的查询我现在：

SELECT `p`.*, `c`.* 
FROM `blog_posts` `p` 
LEFT JOIN (
    SELECT COUNT(*) 
    FROM `blog_comments` `c` 
    WHERE c.post_id = p.id 
) ON `p`.`comments`; 

但它给我错误：

Error Code: 1248. Every derived table must have its own alias 

所以，如果有人可以帮助我，它将非常感激！

---

重要提示 我使用Zend_Db和Zend_Db_Select所以我必须能够使用的功能，如joinLeft()或任何东西，我需要。

这是在我的模型为select()：

$select = $this->table->select(); 

if ($alias) { 
    $select->where('alias = ?', $alias); 
    return $this->table->fetchRow($select); 
} 
if ($withComments) { 
    // I WILL PLACE THE CODE HERE, EXEMPLE: 
    $select->joinLeft(...); 
} 

Answer 1

SELECT p.*, x.* 
FROM blog_posts p 
LEFT JOIN 
(
    SELECT post_id, COUNT(*) as cc 
    FROM blog_comments 
    GROUP BY post_id 
) x 
ON x.post_id = p.id;