MySQL character set viewing and modification tutorial

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)

Method 1:

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)

Method 2:

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)

View the character sets supported by MYSQL

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)

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)

Check the character set of the table

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 | | unknown | | select,insert,update,references | |
| score | int(3) | NULL | YES | | NULL | | select,insert,update,references | |
+-------+----------+-----------------+------+-----+---------+-------+--------------------------------+---------+
5 rows in set (0.00 sec)

Character set for all columns

create database db2 default character set=utf8

mysql> create table test1(id int(6),name char(10)) default character set = 'gbk';
Query OK, 0 rows affected (0.39 sec)

/*Encoding used to establish the connection*/
set character_set_connection=utf8;
/*Database encoding*/
set character_set_database=utf8;
/*Result set encoding*/
set character_set_results=utf8;
/*Database server encoding*/
set character_set_server=utf8;

set character_set_system=utf8;

set collation_connection=utf8;

set collation_database=utf8;

set collation_server=utf8;

Modify the global character set

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)

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 #Original character set 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 #Modified character set 1 row in set (0.00 sec)

Modify the character set of a list

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)

Modify the character set of a field