MySQL操作笔记（3）

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最新推荐文章于 2025-08-08 23:36:14 发布

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分类专栏： MySQL 文章标签： mysql

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MySQL乱码问题

mysql> insert into student values('8','张三','10','') ;
Query OK, 1 row affected, 1 warning (0.00 sec)
mysql> select * from student;
+----+----------+-----+------+
| id | name     | age | dept |
+----+----------+-----+------+
|  1 | zhangsan |  20 | NULL |
|  2 | lisi     |  21 | NULL |
|  3 | zhangss  |  20 | NULL |
|  4 | wangwu   |  30 | NULL |
|  6 | ll       |  12 | NULL |
|  7 | qp       |  10 | NULL |
|  8 | ??       |  10 |      |
+----+----------+-----+------+
7 rows in set (0.00 sec)

mysql> show create table student\G
*************************** 1. row ***************************
       Table: student
Create Table: CREATE TABLE `student` (
  `id` int(4) NOT NULL,
  `name` char(20) NOT NULL,
  `age` tinyint(2) NOT NULL DEFAULT '0',
  `dept` char(20) DEFAULT NULL,
  UNIQUE KEY `ind_id` (`id`),
  KEY `ind_name` (`name`(8)),
  KEY `ind_name_dept` (`name`,`dept`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
1 row in set (0.00 sec)

mysql> set names latin1;
Query OK, 0 rows affected (0.00 sec)

mysql> insert into student values('9','张三','10','') ;
Query OK, 1 row affected (0.00 sec)

mysql> select * from student;
+----+----------+-----+------+
| id | name     | age | dept |
+----+----------+-----+------+
|  1 | zhangsan |  20 | NULL |
|  2 | lisi     |  21 | NULL |
|  3 | zhangss  |  20 | NULL |
|  4 | wangwu   |  30 | NULL |
|  6 | ll       |  12 | NULL |
|  7 | qp       |  10 | NULL |
|  8 | ??       |  10 |      |
|  9 | 张三     |  10 |      |
+----+----------+-----+------+
8 rows in set (0.00 sec)

文件形式

--与库表，系统字符集没有关系
[root@mysql /]# vi test.sql
set names latin1;
insert into student values('10','张四','10','');

mysql> use db
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> system ls -ll /test.sql
-rw-r--r-- 1 root root 69 Nov  9 15:20 /test.sql
mysql> source /test.sql
Query OK, 0 rows affected (0.00 sec)

Query OK, 1 row affected (0.00 sec)

mysql> select * from student;
+----+----------+-----+------+
| id | name     | age | dept |
+----+----------+-----+------+
|  1 | zhangsan |  20 | NULL |
|  2 | lisi     |  21 | NULL |
|  3 | zhangss  |  20 | NULL |
|  4 | wangwu   |  30 | NULL |
|  6 | ll       |  12 | NULL |
|  7 | qp       |  10 | NULL |
|  8 | ??       |  10 |      |
|  9 | 张三     |  10 |      |
| 10 | 张四     |  10 |      |
+----+----------+-----+------+
9 rows in set (0.00 sec)

--
[root@mysql /]# vi test.sql
set names latin1;
insert into student values('11','张四','10','');

[root@mysql /]# mysql -S /data/3306/mysql.sock  -uroot -p123456 --default-character-set=latin1 db < /test.sql

mysql> select * from student;
+----+----------------+-----+------+
| id | name           | age | dept |
+----+----------------+-----+------+
|  1 | zhangsan       |  20 | NULL |
|  2 | lisi           |  21 | NULL |
|  3 | zhangss        |  20 | NULL |
|  4 | wangwu         |  30 | NULL |
|  6 | ll             |  12 | NULL |
|  7 | qp             |  10 | NULL |
|  8 | ??             |  10 |      |
|  9 | å¼ ä¸‰         |  10 |      |
| 10 | å¼ å››         |  10 |      |
| 11 | å¼ å››         |  10 |      |
+----+----------------+-----+------+
10 rows in set (0.00 sec)

mysql> set names latin1;
Query OK, 0 rows affected (0.00 sec)

mysql> select * from student;
+----+----------+-----+------+
| id | name     | age | dept |
+----+----------+-----+------+
|  1 | zhangsan |  20 | NULL |
|  2 | lisi     |  21 | NULL |
|  3 | zhangss  |  20 | NULL |
|  4 | wangwu   |  30 | NULL |
|  6 | ll       |  12 | NULL |
|  7 | qp       |  10 | NULL |
|  8 | ??       |  10 |      |
|  9 | 张三     |  10 |      |
| 10 | 张四     |  10 |      |
| 11 | 张四     |  10 |      |
+----+----------+-----+------+
10 rows in set (0.00 sec)

思想：LINUX、客户端、服务端、库、表、程序字符集统一

--LINUX 建议UTF8
[root@mysql /]# cat /etc/sysconfig/i18n 
LANG="en_US.UTF-8"
SYSFONT="latarcyrheb-sun16"

--MySQL客户端 my.cnf永久，set names临时
mysql>set names latin1
[client]
default-character-set=latin1

--MySQL服务端 my.cnf
[mysqld]
default-character-set=utf8 --5.1以前版本
character-set-server=utf8  --5.5以后版本

--库表
 CREATE DATABASE `db` DEFAULT CHARACTER SET utf8
 Create Table: CREATE TABLE `student` (
  `id` int(4) NOT NULL,
  `name` char(20) NOT NULL,
  `age` tinyint(2) NOT NULL DEFAULT '0',
  `dept` char(20) DEFAULT NULL,
  UNIQUE KEY `ind_id` (`id`),
  KEY `ind_name` (`name`(8)),
  KEY `ind_name_dept` (`name`,`dept`)
 ) ENGINE=InnoDB DEFAULT CHARSET=latin1

mysql字符集

--字符集介绍
GBK     长度2 
UTF-8   长度3
Latin1  长度1
utf8mb4 长度4
[root@mysql /]# mysql -S /data/3306/mysql.sock  -uroot -p123456 -e"show character set;"
+----------+-----------------------------+---------------------+--------+
| 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 |
+----------+-----------------------------+---------------------+--------+

mysql> show variables like 'character_set%';
+--------------------------+-------------------------------------------+
| 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       | /application/mysql-5.5.32/share/charsets/ |
+--------------------------+-------------------------------------------+

--默认与系统字符集一样
character_set_client  
character_set_connection 
character_set_results  
--（1）设置参数登录                           
[root@mysql /]# mysql -S /data/3306/mysql.sock  -uroot -p123456 --default-character-set=latin1
--（2）临时生效
mysql> set names latin1;
Query OK, 0 rows affected (0.00 sec)
--（3）修改客户端，不需重启服务
[client]
default-character-set=latin1

mysql> show variables like 'character_set%';
+--------------------------+-------------------------------------------+
| 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       | /application/mysql-5.5.32/share/charsets/ |
+--------------------------+-------------------------------------------+

修改服务端字符集

[root@mysql 3306]# vi my.cnf
[mysqld]
character-set-server=utf8
[root@mysql 3306]# ./mysql restart
mysql> show variables like 'character_set%';
+--------------------------+-------------------------------------------+
| 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       | /application/mysql-5.5.32/share/charsets/ |
+--------------------------+-------------------------------------------+

修改库表字符集

--不改变原数据字符集
mysql> alter database db character set=utf8;
Query OK, 1 row affected (0.00 sec)

mysql> alter table db.student character set=utf8;
Query OK, 11 rows affected (0.46 sec)
Records: 11  Duplicates: 0  Warnings: 0

总结：修改字符集

1、建库及表结构语句导出，sed批量修改字符集
2、导出所有数据
3、修改mysql服务端和客户端字符集
4、删除原有的库表及数据
5、导入新的建库表语句
6、导入原数据

参数查看修改命令

SHOW [GLOBAL | SESSION] STATUS [like_or_where]
SHOW [GLOBAL | SESSION] VARIABLES [like_or_where]
SET variable_assignment [, variable_assignment] ...
variable_assignment:
      user_var_name = expr
    | [GLOBAL | SESSION] system_var_name = expr
    | [@@global. | @@session. | @@]system_var_name = expr