-- utf8mb4 的编码数据，前三条导出

mysql> set names default;select * from t3 limit 0,3 into outfile '/var/lib/mysql-files/tx.txt';

Query OK, 0 rows affected (0.00 sec)

Query OK, 3 rows affected (0.00 sec)

-- GBK 编码的数据，后三条导出

mysql> set names gbk;select * from t3 limit 3,3 into outfile '/var/lib/mysql-files/ty.txt';

Query OK, 0 rows affected (0.00 sec)

Query OK, 3 rows affected (0.00 sec)

-- 建立一张新表 t4，编码改为统一的 utf8mb4

mysql> create table t4 (a1 varchar(10),a2 varchar(10)) charset utf8mb4;

Query OK, 0 rows affected (0.04 sec)

-- 分别导入两部分数据

mysql> load data infile '/var/lib/mysql-files/tx.txt' into table t4 character set gbk;

Query OK, 3 rows affected (0.01 sec)

Records: 3 Deleted: 0 Skipped: 0 Warnings: 0

mysql> load data infile '/var/lib/mysql-files/ty.txt' into table t4 ;

Query OK, 3 rows affected (0.01 sec)

Records: 3 Deleted: 0 Skipped: 0 Warnings: 0

-- 接下来看结果，一切正常

mysql> set names default;

Query OK, 0 rows affected (0.00 sec)

mysql> select * from t4;

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

| a1 | a2 |

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

| 编码 | 编码 |

| 编码 | 编码 |

| 编码 | 编码 |

| 编码1 | 编码1 |

| 编码1 | 编码2 |

| 编码1 | 编码3 |

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

6 rows in set (0.00 sec)

-- 完了把原来的表删掉，新表 t4 改名即可。

mysql> drop table t3;

Query OK, 0 rows affected (0.04 sec)

mysql> alter table t4 rename to t3;

Query OK, 0 rows affected (0.04 sec)

-- 再次查看记录，一切正常

mysql> select * from t3;

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

| a1 | a2 |

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

| 编码1 | 编码1 |

| 编码1 | 编码2 |

| 编码1 | 编码3 |

| 编码 | 编码 |

| 编码 | 编码 |

| 编码 | 编码 |

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

6 rows in set (0.00 sec)