一、utf8mb4和UTF-8
2.MySQL的“utf8”是一种“专属的编码”，它能够编码的Unicode字符并不多。
二、查看字符集
1.查看MYSQL数据库服务器和数据库字符集
mysql> show variables like '%character%'; +--------------------------+----------------------------+ | Variable_name | Value | +--------------------------+----------------------------+ | character_set_client | latin1 | | character_set_connection | latin1 | | character_set_database | latin1 | | character_set_filesystem | binary | | character_set_results | latin1 | | character_set_server | latin1 | | character_set_system | utf8 | | character_sets_dir | /usr/share/mysql/charsets/ | +--------------------------+----------------------------+ 8 rows in set (0.01 sec) mysql> show variables like 'collation%'; +----------------------+-------------------+ | Variable_name | Value | +----------------------+-------------------+ | collation_connection | latin1_swedish_ci | | collation_database | latin1_swedish_ci | | collation_server | latin1_swedish_ci | +----------------------+-------------------+ 3 rows in set (0.01 sec)
2.查看MYSQL所支持的字符集
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.查看库、表的字符集
语法：show create database 库G;
mysql> show create database confluenceG
*************************** 1. row ***************************
Database: confluence
Create Database: CREATE DATABASE `confluence` /*!40100 DEFAULT CHARACTER SET utf8 COLLATE utf8_bin */
1 row in set (0.00 sec)
语法：show database status from 库名 like 表名;
mysql> mysql> show table status from confluence like 'user_mapping' ; +--------------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+-------------+------------+-----------+----------+----------------+---------+ | 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 | +--------------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+-------------+------------+-----------+----------+----------------+---------+ | user_mapping | InnoDB | 10 | Dynamic | 0 | 0 | 16384 | 0 | 16384 | 0 | NULL | 2020-10-16 03:30:39 | NULL | NULL | utf8_bin | NULL | | | +--------------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+-------------+------------+-----------+----------+----------------+---------+ 1 row in set (0.00 sec)
4.查看表中所有列的字符集
语法：show full columns from 表名;
mysql> show full columns from SECRETS ; +-------+--------------+-----------+------+-----+---------+-------+---------------------------------+---------+ | Field | Type | Collation | Null | Key | Default | Extra | Privileges | Comment | +-------+--------------+-----------+------+-----+---------+-------+---------------------------------+---------+ | key | varchar(255) | utf8_bin | NO | PRI | NULL | | select,insert,update,references | | | value | text | utf8_bin | NO | | NULL | | select,insert,update,references | | +-------+--------------+-----------+------+-----+---------+-------+---------------------------------+---------+ 2 rows in set (0.00 sec)
三、设置字符集（3种方法）
1.创建时指定字符集
创建库的时候指定字符集：
语法：create database 库名 default character set=字符集；
mysql> create database db2 default character set=utf8; Query OK, 1 row affected (0.00 sec)
创建表的时候指定字符集：
语法：create table 表名（属性）default character set = 字符集；
create table test1(id int(6),name char(10)) default character set = 'gbk'; Query OK, 0 rows affected (0.13 sec)
2.创建后指定字符集
修改全局字符集
/*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; /*数据库服务器的编码*/ set character_set_server=utf8; set character_set_system=utf8; set collation_connection=utf8; set collation_database=utf8; set collation_server=utf8;
修改库的字符集
语法：alter database 库名 default character set 字符集;
mysql> alter database confluence default character set gbk; Query OK, 1 row affected (0.01 sec)
修改表的字符集
语法：alter table 表名 convert to character set 字符集;
alter table test1 convert to character set utf8;
修改字段的字符集
语法：alter table 表名 modify 字段名 字段属性 character set gbk；
alter table test1 modify name char(10) character set gbk;
3.my.ncf配置文件中修改
character-set-server = utf8 #定义服务端所使用的字符集为UTF8 #定义client与server之间传递字符的编码规则为utf8 init_connect = SET NAMES utf8