各种修改Mysql字符集

　　以下方法最好在没有数据时操作，否则有可能导致乱码。如果已有数据，做好备份尝试Mysql迁移由于字符集导致乱码的数据

　　创建测试环境

mysql> create database test_db;
Query OK, 1 row affected (0.00 sec)

mysql> use test_db;
Database changed
mysql> create table test_table(id int,name varchar(20));
Query OK, 0 rows affected (0.03 sec)

mysql> insert into test_table values(1,"zhangsan");
Query OK, 1 row affected (0.00 sec)

(1).查看字符集

1）查看Mysql客户端、Mysql服务器和Mysql数据库的默认字符集

mysql> show VARIABLES like 'character%';
+--------------------------+----------------------------+
| Variable_name            | Value                      |
+--------------------------+----------------------------+
| character_set_client     | utf8                       |　　　　//客户端使用的编码
| character_set_connection | utf8                       |　　　　//连接时使用的编码
| character_set_database   | latin1                     |　　　　//数据库使用的编码
| character_set_filesystem | binary                     |
| character_set_results    | utf8                       |　　　　//结果集使用的编码
| character_set_server     | latin1                     |　　　　//服务器使用的编码
| character_set_system     | utf8                       |
| character_sets_dir       | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+
8 rows in set (0.00 sec)

　　还可以show variables like 'collation%';

mysql> show variables like 'collation%';
+----------------------+-------------------+
| Variable_name        | Value             |
+----------------------+-------------------+
| collation_connection | utf8_general_ci   |
| collation_database   | latin1_swedish_ci |
| collation_server     | latin1_swedish_ci |
+----------------------+-------------------+
3 rows in set (0.00 sec)

2）查看Mysql支持的字符集

mysql> show charset;
+----------+---------------------------------+---------------------+--------+
| Charset  | Description                     | Default collation   | Maxlen |
+----------+---------------------------------+---------------------+--------+
| big5     | Big5 Traditional Chinese        | big5_chinese_ci     |      2 |
| dec8     | DEC West European               | dec8_swedish_ci     |      1 |
| cp850    | DOS West European               | cp850_general_ci    |      1 |
| hp8      | HP West European                | hp8_english_ci      |      1 |
| koi8r    | KOI8-R Relcom Russian           | koi8r_general_ci    |      1 |
| latin1   | cp1252 West European            | latin1_swedish_ci   |      1 |
| latin2   | ISO 8859-2 Central European     | latin2_general_ci   |      1 |
| swe7     | 7bit Swedish                    | swe7_swedish_ci     |      1 |
| ascii    | US ASCII                        | ascii_general_ci    |      1 |
| ujis     | EUC-JP Japanese                 | ujis_japanese_ci    |      3 |
| sjis     | Shift-JIS Japanese              | sjis_japanese_ci    |      2 |
| hebrew   | ISO 8859-8 Hebrew               | hebrew_general_ci   |      1 |
| tis620   | TIS620 Thai                     | tis620_thai_ci      |      1 |
| euckr    | EUC-KR Korean                   | euckr_korean_ci     |      2 |
| koi8u    | KOI8-U Ukrainian                | koi8u_general_ci    |      1 |
| gb2312   | GB2312 Simplified Chinese       | gb2312_chinese_ci   |      2 |
| greek    | ISO 8859-7 Greek                | greek_general_ci    |      1 |
| cp1250   | Windows Central European        | cp1250_general_ci   |      1 |
| gbk      | GBK Simplified Chinese          | gbk_chinese_ci      |      2 |
| latin5   | ISO 8859-9 Turkish              | latin5_turkish_ci   |      1 |
| armscii8 | ARMSCII-8 Armenian              | armscii8_general_ci |      1 |
| utf8     | UTF-8 Unicode                   | utf8_general_ci     |      3 |
| ucs2     | UCS-2 Unicode                   | ucs2_general_ci     |      2 |
| cp866    | DOS Russian                     | cp866_general_ci    |      1 |
| keybcs2  | DOS Kamenicky Czech-Slovak      | keybcs2_general_ci  |      1 |
| macce    | Mac Central European            | macce_general_ci    |      1 |
| macroman | Mac West European               | macroman_general_ci |      1 |
| cp852    | DOS Central European            | cp852_general_ci    |      1 |
| latin7   | ISO 8859-13 Baltic              | latin7_general_ci   |      1 |
| utf8mb4  | UTF-8 Unicode                   | utf8mb4_general_ci  |      4 |
| cp1251   | Windows Cyrillic                | cp1251_general_ci   |      1 |
| utf16    | UTF-16 Unicode                  | utf16_general_ci    |      4 |
| utf16le  | UTF-16LE Unicode                | utf16le_general_ci  |      4 |
| cp1256   | Windows Arabic                  | cp1256_general_ci   |      1 |
| cp1257   | Windows Baltic                  | cp1257_general_ci   |      1 |
| utf32    | UTF-32 Unicode                  | utf32_general_ci    |      4 |
| binary   | Binary pseudo charset           | binary              |      1 |
| geostd8  | GEOSTD8 Georgian                | geostd8_general_ci  |      1 |
| cp932    | SJIS for Windows Japanese       | cp932_japanese_ci   |      2 |
| eucjpms  | UJIS for Windows Japanese       | eucjpms_japanese_ci |      3 |
| gb18030  | China National Standard GB18030 | gb18030_chinese_ci  |      4 |
+----------+---------------------------------+---------------------+--------+
41 rows in set (0.00 sec)

3）查看已存在的数据库的字符集

　　show create database [数据库名];

mysql> show create database test_db;
+----------+--------------------------------------------------------------------+
| Database | Create Database                                                    |
+----------+--------------------------------------------------------------------+
| test_db  | CREATE DATABASE `test_db` /*!40100 DEFAULT CHARACTER SET latin1 */ |
+----------+--------------------------------------------------------------------+
1 row in set (0.00 sec)

4）查看已存在的数据表的字符集

　　show table status from [数据库名] like '[表名]';

mysql> show table status from test_db like 'test_table';
+------------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+---------------------+------------+-------------------+----------+----------------+---------+
| Name       | Engine | Version | Row_format | Rows | Avg_row_length | Data_length | Max_data_length | Index_length | Data_free | Auto_increment | Create_time         | Update_time         | Check_time | Collation         | Checksum | Create_options | Comment |
+------------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+---------------------+------------+-------------------+----------+----------------+---------+
| test_table | InnoDB |      10 | Dynamic    |    1 |          16384 |       16384 |               0 |            0 |         0 |           NULL | 2019-06-04 09:55:25 | 2019-06-04 09:55:35 | NULL       | latin1_swedish_ci |     NULL |                |         |
+------------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+---------------------+------------+-------------------+----------+----------------+---------+
1 row in set (0.00 sec)

　　还可以使用show create table [数据库名].[表名];

mysql> show create table test_db.test_table;
+------------+-----------------------------------------------------------------------------------------------------------------------------------+
| Table      | Create Table                                                                                                                      |
+------------+-----------------------------------------------------------------------------------------------------------------------------------+
| test_table | CREATE TABLE `test_table` (
  `id` int(11) DEFAULT NULL,
  `name` varchar(20) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+------------+-----------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

5）查看已存在的数据表中列的字符集

　　show full columns from [数据库名].[表名];

mysql> show full columns from test_db.test_table;
+-------+-------------+-------------------+------+-----+---------+-------+---------------------------------+---------+
| Field | Type        | Collation         | Null | Key | Default | Extra | Privileges                      | Comment |
+-------+-------------+-------------------+------+-----+---------+-------+---------------------------------+---------+
| id    | int(11)     | NULL              | YES  |     | NULL    |       | select,insert,update,references |         |
| name  | varchar(20) | latin1_swedish_ci | YES  |     | NULL    |       | select,insert,update,references |         |
+-------+-------------+-------------------+------+-----+---------+-------+---------------------------------+---------+
2 rows in set (0.00 sec)

(2).修改字符集

1）修改默认字符集

　　临时修改，set [参数名]=[编码];

//建立连接使用的编码
set character_set_connection=utf8;
//数据库的编码
set character_set_database=utf8;
//结果集的编码
set character_set_results=utf8;
//Mysql服务器的编码
set character_set_server=utf8;
set character_set_system=utf8;
set collation_connection=utf8;
set collation_database=utf8;
set collation_server=utf8;

　　永久修改，修改配置文件/etc/my.cnf，在[mysqld]模块内添加一行[参数名]=[编码]，然后重启mysqld服务。另外如果在配置文件找那个设置character_set_server=utf8，那么数据库默认字符集也会变为utf8。

mysql> show VARIABLES like 'character%';
+--------------------------+----------------------------+
| Variable_name            | Value                      |
+--------------------------+----------------------------+
| character_set_client     | utf8                       |
| character_set_connection | utf8                       |
| character_set_database   | utf8                       |
| character_set_filesystem | binary                     |
| character_set_results    | utf8                       |
| character_set_server     | utf8                       |
| character_set_system     | utf8                       |
| character_sets_dir       | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+
8 rows in set (0.01 sec)

2）修改已存在的数据库的字符集

　　alter database [数据库名] default character set [字符集];

mysql> show create database test_db;
+----------+--------------------------------------------------------------------+
| Database | Create Database                                                    |
+----------+--------------------------------------------------------------------+
| test_db  | CREATE DATABASE `test_db` /*!40100 DEFAULT CHARACTER SET latin1 */ |
+----------+--------------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> alter database test_db default character set utf8;
Query OK, 1 row affected (0.00 sec)

mysql> show create database test_db;
+----------+------------------------------------------------------------------+
| Database | Create Database                                                  |
+----------+------------------------------------------------------------------+
| test_db  | CREATE DATABASE `test_db` /*!40100 DEFAULT CHARACTER SET utf8 */ |
+----------+------------------------------------------------------------------+
1 row in set (0.00 sec)

3）修改已存在的数据表字符集

　　alter table [数据库名].[表名] convert to character set [字符集];

mysql> show create table test_db.test_table;
+------------+-----------------------------------------------------------------------------------------------------------------------------------+
| Table      | Create Table                                                                                                                      |
+------------+-----------------------------------------------------------------------------------------------------------------------------------+
| test_table | CREATE TABLE `test_table` (
  `id` int(11) DEFAULT NULL,
  `name` varchar(20) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+------------+-----------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> alter table test_db.test_table convert to character set utf8;
Query OK, 1 row affected (0.06 sec)
Records: 1  Duplicates: 0  Warnings: 0

mysql> show create table test_db.test_table;
+------------+---------------------------------------------------------------------------------------------------------------------------------+
| Table      | Create Table                                                                                                                    |
+------------+---------------------------------------------------------------------------------------------------------------------------------+
| test_table | CREATE TABLE `test_table` (
  `id` int(11) DEFAULT NULL,
  `name` varchar(20) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8 |
+------------+---------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

4）修改列的字符集

　　alter table [数据库名].[表名] modify [字段名] [字段属性] character set [字符集];

mysql> show full columns from test_db.test_table;
+-------+-------------+-----------------+------+-----+---------+-------+---------------------------------+---------+
| Field | Type        | Collation       | Null | Key | Default | Extra | Privileges                      | Comment |
+-------+-------------+-----------------+------+-----+---------+-------+---------------------------------+---------+
| id    | int(11)     | NULL            | YES  |     | NULL    |       | select,insert,update,references |         |
| name  | varchar(20) | utf8_general_ci | YES  |     | NULL    |       | select,insert,update,references |         |
+-------+-------------+-----------------+------+-----+---------+-------+---------------------------------+---------+
2 rows in set (0.01 sec)

mysql> alter table test_db.test_table modify name varchar(20) character set gbk;
Query OK, 1 row affected (0.02 sec)
Records: 1  Duplicates: 0  Warnings: 0

mysql> show full columns from test_db.test_table;
+-------+-------------+----------------+------+-----+---------+-------+---------------------------------+---------+
| Field | Type        | Collation      | Null | Key | Default | Extra | Privileges                      | Comment |
+-------+-------------+----------------+------+-----+---------+-------+---------------------------------+---------+
| id    | int(11)     | NULL           | YES  |     | NULL    |       | select,insert,update,references |         |
| name  | varchar(20) | gbk_chinese_ci | YES  |     | NULL    |       | select,insert,update,references |         |
+-------+-------------+----------------+------+-----+---------+-------+---------------------------------+---------+
2 rows in set (0.01 sec)

　　

参考：MySQL查看和修改字符集的方法，作者：明王不动心