2,MySQL查看和修改字符集的方法及修改阿里云字符集
一、查看字符集
系统变量：
– character_set_server：默认的内部操作字符集
– character_set_client：客户端来源数据使用的字符集
– character_set_connection：连接层字符集
– character_set_results：查询结果字符集
– character_set_database：当前选中数据库的默认字符集
– character_set_system：系统元数据(字段名等)字符集
– 还有以collation_开头的同上面对应的变量，用来描述字符序。
show global variables like '%char%'; #查看RDS实例字符集相关参数设置
show global variables like 'coll%'; #查看当前会话字符序相关参数设置
show character set; #查看实例支持的字符集
show collation; #查看实例支持的字符序
show create table [\(Table_Name]; #查看表字符集设置 show create database [\)Database_Name]; #查看数据库字符集设置
show procedure status; #显示数据库中所有存储过程的基本信息
show create procedure [$Procedure_Name]; #显示某一个存储过程的详细信息
alter database db_name default charset utf8; #修改数据库的字符集
create database db_name character set utf8; #创建数据库时指定字符集
alter table tab_name default charset utf8 collate utf8_general_ci; #修改表字符集和字符序
1.查看MYSQL数据库服务器和数据库字符集
方法一：show variables like '%character%';
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/local/mysql5535/share/charsets/ |
+--------------------------+--------------------------------------+
8 rows in set (0.00 sec)
方法二：show variables like 'collation%';
mysql> show variables like 'collation%';
+----------------------+-----------------+
| Variable_name | Value |
+----------------------+-----------------+
| collation_connection | utf8_general_ci |
| collation_database | utf8_general_ci |
| collation_server | utf8_general_ci |
+----------------------+-----------------+
3 rows in set (0.00 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 |
| 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 |
+----------+-----------------------------+---------------------+--------+
39 rows in set (0.00 sec)
3.查看库的字符集
语法：show database status from 库名 like 表名;
mysql> show create database shiyan\G
*************************** 1. row ***************************
Database: shiyan
Create Database: CREATE DATABASE `shiyan` /*!40100 DEFAULT CHARACTER SET gbk */
1 row in set (0.00 sec)
4.查看表的字符集
语法：show table status from 库名 like 表名;
mysql> show table status from class_7 like 'test_info';
+-----------+--------+---------+------------+------+----------------+-------------------------+-------------+------------+-----------------+----------+-
| Name | Engine | Version | Row_format | Rows | Avg_row_length | Data_leate_time | Update_time | Check_time | Collation | Checksum |
+-----------+--------+---------+------------+------+----------------+-------------------------+-------------+------------+-----------------+----------+-
| test_info | InnoDB | 10 | Compact | 10 | 1638 | 17-12-05 19:01:55 | NULL | NULL | utf8_general_ci | NULL |
+-----------+--------+---------+------------+------+----------------+-------------------------+-------------+------------+-----------------+----------+-
1 row in set (0.00 sec)
5.查看表中所有列的字符集
语法：show full columns from 表名;
mysql> show full columns from test_info;
+-------+----------+-----------------+------+-----+---------+-------+---------------------------------+---------+
| Field | Type | Collation | Null | Key | Default | Extra | Privileges | Comment |
+-------+----------+-----------------+------+-----+---------+-------+---------------------------------+---------+
| id | int(3) | NULL | NO | PRI | NULL | | select,insert,update,references | |
| name | char(12) | utf8_general_ci | YES | | NULL | | select,insert,update,references | |
| dorm | char(10) | utf8_general_ci | YES | | NULL | | select,insert,update,references | |
| addr | char(12) | utf8_general_ci | YES | | 未知 | | select,insert,update,references | |
| score | int(3) | NULL | YES | | NULL | | select,insert,update,references | |
+-------+----------+-----------------+------+-----+---------+-------+---------------------------------+---------+
5 rows in set (0.00 sec)
二、设置字符集
设置字符集一般有两种方法，一种是在创建表的时候设置字符集，另一种是表建成之后修改字符集。
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；
create database db2 default character set=utf8
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；
mysql> create table test1(id int(6),name char(10)) default character set = 'gbk';
Query OK, 0 rows affected (0.39 sec)
2.修改字符集
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;
alter database shiyan default character set gbk;
mysql> show create database shiyan\G
*************************** 1. row ***************************
Database: shiyan
Create Database: CREATE DATABASE `shiyan` /*!40100 DEFAULT CHARACTER SET utf8 */
1 row in set (0.00 sec)
mysql> alter database shiyan default character set gbk;
Query OK, 1 row affected (0.00 sec)
mysql> show create database shiyan\G
*************************** 1. row ***************************
Database: shiyan
Create Database: CREATE DATABASE `shiyan` /*!40100 DEFAULT CHARACTER SET gbk */
1 row in set (0.00 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;
mysql> show create table test1\G
*************************** 1. row ***************************
Table: test1
Create Table: CREATE TABLE `test1` (
`id` int(6) DEFAULT NULL,
`name` char(10) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=gbk #原字符集
1 row in set (0.00 sec)
mysql> alter table test1 convert to character set utf8;
Query OK, 0 rows affected (0.58 sec)
Records: 0 Duplicates: 0 Warnings: 0
mysql> show create table test1\G
*************************** 1. row ***************************
Table: test1
Create Table: CREATE TABLE `test1` (
`id` int(6) DEFAULT NULL,
`name` char(10) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8 #修改后的字符集
1 row in set (0.00 sec)
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;
mysql> show full columns from test1;
+-------+----------+-----------------+------+-----+---------+-------+---------------------------------+---------+
| Field | Type | Collation | Null | Key | Default | Extra | Privileges | Comment |
+-------+----------+-----------------+------+-----+---------+-------+---------------------------------+---------+
| id | int(6) | NULL | YES | | NULL | | select,insert,update,references | |
| name | char(10) | utf8_general_ci | YES | | NULL | | select,insert,update,references | |
+-------+----------+-----------------+------+-----+---------+-------+---------------------------------+---------+
2 rows in set (0.01 sec)
mysql> alter table test1 modify name char(10) character set gbk;
Query OK, 0 rows affected (0.58 sec)
Records: 0 Duplicates: 0 Warnings: 0
mysql> show full columns from test1;
+-------+----------+----------------+------+-----+---------+-------+---------------------------------+---------+
| Field | Type | Collation | Null | Key | Default | Extra | Privileges | Comment |
+-------+----------+----------------+------+-----+---------+-------+---------------------------------+---------+
| id | int(6) | NULL | YES | | NULL | | select,insert,update,references | |
| name | char(10) | gbk_chinese_ci | YES | | NULL | | select,insert,update,references | |
+-------+----------+----------------+------+-----+---------+-------+---------------------------------+---------+
2 rows in set (0.01 sec)
概述
本文主要介绍RDS MySQL如何使用utf8mb4字符集存储emoji表情。
详细信息
阿里云提醒您：
如果您对实例或数据有修改、变更等风险操作，务必注意实例的容灾、容错能力，确保数据安全。
如果您对实例（包括但不限于ECS、RDS）等进行配置与数据修改，建议提前创建快照或开启RDS日志备份等功能。
如果您在阿里云平台授权或者提交过登录账号、密码等安全信息，建议您及时修改。
基本原则
如果要实现存储emoji表情到RDS MySQL实例，需要客户端、到RDS实例的会话连接、RDS实例三个方面统一使用utf8mb4字符集。
客户端：客户端需要保证输出字符串的字符集为utf8mb4。
到RDS实例的会话连接：支持utf8mb4字符集。以常见的JDBC连接为例，需要使用MySQL Connector/J 5.1.13及以上的版本，JDBC的连接串中，建议不配置characterEncoding选项。
RDS实例：在RDS控制台将character_set_server参数设置为utf8mb4，且数据库和表的字符集也要设置为utf8mb4。
修改字符集
如果字符集不符合以上基本原则，请参见RDS MySQL字符集相关说明修改字符集。
说明：由utf8修改为utf8mb4字符集不会影响之后的数据质量，且已经存在的数据也不受影响，但是数据存储空间会有所增加。
适用于
云数据库RDS MySQL版
浙公网安备 33010602011771号