数据库Mysql的字符集问题汇总

１．初始化创建数据库字符集

set character_set_database=utf8;
set character_set_server=utf8;
set character_set_client=gbk;
set character_set_connection=gbk;
set character_set_client=utf8;
set character_set_connection=utf8;​​

当我们在一个新的数据库下，新建需要支持中文的数据库时，先设置一下字符集，否则会出现插入中文失败的情况。
如何查看未创建数据库前查看字符集的选项。
１．查看Mysql数据库服务和数据库字符集
方法一：

show variables like '%character%';​

方法二：

show variables like 'collation%';

执行结果：
方法一：

mysql> show variables like '%character%';
+--------------------------+----------------------------+
| Variable_name | Value |
+--------------------------+----------------------------+
| character_set_client | utf8 |
| character_set_connection | utf8 |
| character_set_database | latin1 |
| character_set_filesystem | binary |
| character_set_results | utf8 |
| character_set_server | latin1 |
| character_set_system | utf8 |
| character_sets_dir | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+
8 rows in set (0.01 sec)
mysql>​

方法二：

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)
mysql>​

２．查看Mysql所支持的字符集
语法：

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.查看库的字符集
语法:

show　create database student\G​

执行结果：

mysql> show create database student\G
*************************** 1. row ***************************
Database: student
Create Database: CREATE DATABASE `student` /*!40100 DEFAULT CHARACTER SET utf8 */
1 row in set (0.00 sec)
mysql> 

4.查看表的字符集
语法：

show table status from 库名 like  表名;​

执行结果：

mysql> show table status from student like 'C';
+------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+-------------+------------+-----------------+----------+----------------+---------+
| 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 |
+------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+-------------+------------+-----------------+----------+----------------+---------+
| C | InnoDB | 10 | Dynamic | 2 | 8192 | 16384 | 0 | 0 | 0 | NULL | 2019-10-27 18:54:33 | 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;​

执行结果：

mysql> show full columns from C;
+---------+----------+-----------------+------+-----+---------+-------+---------------------------------+---------+
| Field | Type | Collation | Null | Key | Default | Extra | Privileges | Comment |
+---------+----------+-----------------+------+-----+---------+-------+---------------------------------+---------+
| cno | char(10) | utf8_general_ci | NO | PRI | NULL | | select,insert,update,references | |
| cname | char(20) | utf8_general_ci | YES | | NULL | | select,insert,update,references | |
| ccredit | int(11) | NULL | YES | | NULL | | select,insert,update,references | |
+---------+----------+-----------------+------+-----+---------+-------+---------------------------------+---------+
3 rows in set (0.00 sec)
mysql>​

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=utf-8

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；

执行结果：

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（全局）

/*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;
修改全局字符集​

修改库的字符集
语法：

alter adtabase 库名 default character set gbk;​

执行结果：

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;​

例子：

alter table test1 convert to character set utf8; 

执行结果：

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；​

执行结果：

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 | |
+-------+----------+-----------------+------+-----+---------+-------+---------------------------------+---------+
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 | |
+-------+----------+----------------+------+-----+---------+-------+---------------------------------+---------+
rows in set (0.01 sec)
修改字段的字符集​

如果出现导入错误的方式：执行这句:

set names gbk;

参考自：https://www.cnblogs.com/yangmingxianshen/p/7999428.html
参考自：http://leanote.com/blog/post/5dc61cf1ab64414443000064
第二个为我自己的博客笔记。

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