Mysql加入覆盖提交ID

Question

我有2个表。 submissions和users。他们通过submissions.user_id = users.id相关。

users：

+----------------+------------------------+------+-----+-------------------+-----------------------------+ 
| Field   | Type     | Null | Key | Default   | Extra      | 
+----------------+------------------------+------+-----+-------------------+-----------------------------+ 
| id    | int(10) unsigned  | NO | PRI | NULL    | auto_increment    | 
| email   | varchar(128)   | NO | MUL | NULL    |        | 
| hash   | varchar(64)   | NO |  | NULL    |        | 
| salt   | varchar(32)   | NO |  | NULL    |        | 
| username  | varchar(23)   | NO |  | NULL    |        | 
| type   | enum('normal','admin') | NO |  | normal   |        | 
| about   | varchar(255)   | NO |  | NULL    |        | 
| created  | datetime    | NO |  | NULL    |        | 
| last_login  | timestamp    | NO |  | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP | 
| created_ip  | int(10) unsigned  | NO |  | NULL    |        | 
| last_login_ip | int(10) unsigned  | NO |  | NULL    |        | 
| remember_me | tinyint(3) unsigned | NO |  | 0     |        | 
| avatar   | varchar(32)   | NO |  | NULL    |        | 
| confirmed  | tinyint(1) unsigned | NO |  | 0     |        | 
| confirm_code | varchar(64)   | NO |  | NULL    |        | 
| public_profile | tinyint(1)    | NO |  | 1     |        | 
+----------------+------------------------+------+-----+-------------------+-----------------------------+ 

submissions

+-------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+------+-----+---------+----------------+ 
| Field  | Type                                                                  | Null | Key | Default | Extra   | 
+-------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+------+-----+---------+----------------+ 
| id   | int(10) unsigned                                                               | NO | PRI | NULL | auto_increment | 
| title  | varchar(255)                                                                | NO |  | NULL |    | 
| slug  | varchar(255)                                                                | NO |  | NULL |    | 
| description | mediumtext                                                                | NO |  | NULL |    | 
| user_id  | int(11)                                                                 | NO | MUL | NULL |    | 
| created  | datetime                                                                 | NO |  | NULL |    | 
| category | enum('animals-pets','autos-vehicles','careers-work','clothing','computers','cooking-food','deals','education','electronics','entertainment','general-advice','finance','health-fitness','hygiene','home-garden','how-to','misc','self-improvement','sports','traveling') | NO |  | NULL |    | 
| type  | enum('tip','request')                                                             | NO |  | NULL |    | 
| thumbnail | varchar(64)                                                                | NO |  | NULL |    | 
| removed  | tinyint(1) unsigned                                                              | NO |  | 0  |    | 
| down_votes | int(10) unsigned                                                               | NO |  | 0  |    | 
| up_votes | int(10) unsigned                                                               | NO |  | 0  |    | 
| score  | int(11)                                                                 | NO | MUL | 0  |    | 
| keywords | varchar(255)                                                                | NO |  | NULL |    | 
| ip   | int(10) unsigned                                                               | NO |  | NULL |    | 
+-------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+------+-----+---------+----------------+ 

我想加入的两个表查看提交，但结果我得到了下面的查询给了我这样的：

SELECT s.*, u.id, u.username FROM submissions s JOIN users u ON s.user_id = u.id WHERE s.id = 12'

总会给我：

{ id: 15, 
    title: 'what the hell!', 
    slug: 'what-the-hell', 
    description: 'seriously what the hell node mysql?!', 
    user_id: 15, 
    created: Sat Jan 11 2014 11:58:06 GMT-0800 (PST), 
    category: 'misc', 
    thumbnail: '', 
    removed: 0, 
    down_votes: 0, 
    up_votes: 0, 
    score: 0, 
    keywords: '!', 
    ip: 127001, 
    username: 'blahbster'} 

它会永远让submission.id获取这是user.id.时它为什么会覆盖？

Answer 1

这是“覆盖”，因为两列具有相同的名称，id，并且无法区分它们。

只需使用：

SELECT s.*, u.username 
FROM submissions s JOIN 
    users u 
    ON s.user_id = u.id 
WHERE s.id = 12; 

而且使用user_id用户ID和id的订阅ID。