mysql在一个有多种关系的情况下检索相同的记录

Question

I have a contacts table and a codes table. A contact has many codes:

mysql> DESCRIBE contacts;
+------------------------+--------------+------+-----+---------+----------------+
| Field                  | Type         | Null | Key | Default | Extra          |
+------------------------+--------------+------+-----+---------+----------------+
| id                     | int(11)      | NO   | PRI | NULL    | auto_increment |
| first_name             | varchar(255) | YES  |     | NULL    |                |
| last_name              | varchar(255) | YES  |     | NULL    |                |
| email                  | varchar(255) | YES  |     | NULL    |  


mysql> DESCRIBE codes;
+-----------------------------+--------------+------+-----+---------+----------------+
| Field                       | Type         | Null | Key | Default | Extra          |
+-----------------------------+--------------+------+-----+---------+----------------+
| id                          | int(11)      | NO   | PRI | NULL    | auto_increment |
| code                        | varchar(255) | YES  |     | NULL    |                |
| contact_id                  | int(11)      | YES  |     | NULL    |                |

I can retrieve all contacts who have codes:

SELECT * FROM `contacts` 
INNER JOIN `classification_codes` 
ON `contacts`.`id` = `codes`.`contact_id`;

Unfortunately, this will return only unique contact records even if the contact has many codes. If, for example, the contact has two codes, I want to retrieve the same contact record twice, with each record associated separately with each code. How can I accomplish this in mysql?

Answer 1

Change order of tables to get all codes that has contacts. That should do the trick

Answer 2

Just change tables order:

SELECT * FROM `classification_codes` 
INNER JOIN `contacts`  
ON `contacts`.`id` = `codes`.`contact_id`;