在实际应用中，很可能会碰到一些需要删除某些字段的重复记录，我现在把我能想到的写下来，望高手们补充。

1、
具体实现如下：
Table         Create Table                                            
------------  --------------------------------------------------------
users_groups  CREATE TABLE `users_groups` (                           
                `id` int(10) unsigned NOT NULL AUTO_INCREMENT,        
                `uid` int(11) NOT NULL,                               
                `gid` int(11) NOT NULL,                               
                PRIMARY KEY (`id`)                                    
              ) ENGINE=InnoDB AUTO_INCREMENT=15 DEFAULT CHARSET=utf8  

users_groups.txt内容：
1,11,502
2,107,502
3,100,503
4,110,501
5,112,501
6,104,502
7,100,502
8,100,501
9,102,501
10,104,502
11,100,502
12,100,501
13,102,501
14,110,501
mysql> load data infile 'c:\users_groups.txt' into table users_groups fields
rminated by ',' lines terminated by ' ';
Query OK, 14 rows affected (0.05 sec)
Records: 14  Deleted: 0  Skipped: 0  Warnings: 0

mysql> select * from users_groups;

query result(14 records)
id uid gid
1 11 502
2 107 502
3 100 503
4 110 501
5 112 501
6 104 502
7 100 502
8 100 501
9 102 501
10 104 502
11 100 502
12 100 501
13 102 501
14 110 501
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