MySQL 创建唯一索引忽略对已经重复数据的检查

在创建唯一索引的基础上加上关键字"IGNORE "即可。(注意，经测试，在5.7版本已经不再支持该参数)

# 重复数据

mysql> select aid,count(aid) as total ,email,tel_no,account_type,exten,passwd  from fudao_admin    group by user_name having total> 1;

+-------+-------+--------------------------+--------+--------------+-------+----------------------------------+

| aid   | total | email                    | tel_no | account_type | exten | passwd                           |

+-------+-------+--------------------------+--------+--------------+-------+----------------------------------+

|   256 |     5 |                          |        |            0 |       |                                  |

|  4712 |     2 | [email protected]     | 0      |            0 |       | 1afc079897c2de73022540f7c31db632 |

|  1070 |     2 | [email protected]   |        |            0 |       | c81103a50f7b7748303ede9726eed91a |

| 10429 |     2 | [email protected] | 0      |            0 | 1090  | 9bd7aa138ff1486e1285a412bda934dd |

| 10425 |     2 | [email protected]         | 0      |            0 |       | 96e79218965eb72c92a549dd5a330112 |

| 10426 |     2 | [email protected]         | 0      |            0 |       | 96e79218965eb72c92a549dd5a330112 |

|  1402 |     2 | [email protected]     |        |            0 |       | 72d1e186ab204c937ea48a3ff9f926fa |

|  3385 |     2 | [email protected]     | 0      |            0 |       | 263cad88649b39ed9fc95739c4f20edc |

+-------+-------+--------------------------+--------+--------------+-------+----------------------------------+

8 rows in set (0.25 sec)

mysql> ALTER IGNORE TABLE fudao_admin ADD UNIQUE `uq_user_name` (user_name);

Query OK, 13530 rows affected, 1 warning (0.44 sec)

Records: 13530  Duplicates: 11  Warnings: 1

mysql> select aid,count(aid) as total ,email,tel_no,account_type,exten,passwd  from fudao_admin    group by user_name having total> 1;

Empty set (0.08 sec)