MYSQL常用命令（一）

Mysql的运行环境：Centos6.5版本
一、MySQL数据库基础
1.安装Mysql。

yum install mysql-server.i686

2.启动Mysql服务

service mysqld start

3.关闭Mysql服务

service mysqld stop

4.创建库的基本语句：

create database 库名;

5.使用库：

use 库名;

6.建表基本语法：

create table 表名(
字段1 列类型1，
字段2 列类型2，
...
字段n 列类型n
);

7.向表中插入数据：

insert into 表名(字段名1，字段2,...) values(values1,values2);

8.查看表中的数据：

select * from 表名;

二 、库的操作
1.创建一个使用utf8字符集的数据库company

mysql> create database company charset=utf8;
Query OK, 1 row affected (0.00 sec)

2.创建一个使用utf8字符集并带校验规则的数据库company1

mysql> create database company1 charset=utf8 collate utf8_general_ci;
Query OK, 1 row affected (0.01 sec)

3.查看数据库支持哪些字符集：

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 |
| cp1251   | Windows Cyrillic            | cp1251_general_ci   |      1 |
| cp1256   | Windows Arabic              | cp1256_general_ci   |      1 |
| cp1257   | Windows Baltic              | cp1257_general_ci   |      1 |
| 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 |
+----------+-----------------------------+---------------------+--------+
36 rows in set (0.00 sec)

校验规则：
1.区分大小写
创建一个数据库，校验规则使用utf8_general_ci[不区分大小写]

mysql> create database bbb collate utf8_general_ci;
Query OK, 1 row affected (0.00 sec)

mysql> use bbb;
Database changed
mysql> create table person(name varchar(20));
Query OK, 0 rows affected (0.01 sec)

mysql> insert into person values('a');
Query OK, 1 row affected (0.00 sec)

mysql> insert into person values('A');
Query OK, 1 row affected (0.00 sec)

mysql> select * from person where name='a';
+------+
| name |
+------+
| a    |
| A    |
+------+
2 rows in set (0.00 sec)

创建一个数据库，校验规则使用utf8_general_bin[区分大小写]

mysql> create database aaa collate utf8_bin;
Query OK, 1 row affected (0.00 sec)

mysql> use aaa;
Database changed
mysql> create table person(name varchar(20));
Query OK, 0 rows affected (0.00 sec)

mysql> insert into person values('a');
Query OK, 1 row affected (0.00 sec)

mysql> insert into person values('A');
Query OK, 1 row affected (0.00 sec)

mysql> select * from person where name='a';
+------+
| name |
+------+
| a    |
+------+
1 row in set (0.00 sec)

2.影响排序

mysql> insert into person values('b');
Query OK, 1 row affected (0.00 sec)

mysql> insert into person values('B');
Query OK, 1 row affected (0.00 sec)

mysql> select * from person order by name;
+------+
| name |
+------+
| a    |
| A    |
| b    |
| B    |
+------+
4 rows in set (0.00 sec)

mysql> insert into person values('b');
Query OK, 1 row affected (0.00 sec)

mysql> insert into person values('B');
Query OK, 1 row affected (0.00 sec)

mysql> select * from person order by name;
+------+
| name |
+------+
| A    |
| B    |
| a    |
| b    |
+------+
4 rows in set (0.00 sec)

数据库的操作
1.查看数据库：

show databases;

2.显示创建的数据库：

show create database 数据库名;

3.删除数据库：

drop database 数据库名;

4.查看当前Mysql数据库的链接情况：

show processlist;

例：

mysql> show processlist;
+----+------+-----------+------+---------+------+-------+------------------+
| Id | User | Host      | db   | Command | Time | State | Info             |
+----+------+-----------+------+---------+------+-------+------------------+
|  2 | root | localhost | aaa  | Query   |    0 | NULL  | show processlist |
+----+------+-----------+------+---------+------+-------+------------------+
1 row in set (0.00 sec)

5.备份和恢复数据库
注：在根用户模式下操作，且不输入密码。

[root@localhost admin]# mysqldump -u root -p 数据库名 >./存放路径   #备份

例：

[root@localhost admin]# mysqldump -u root -p aaa >./aaa.sql
Enter password: 

恢复数据库，进入mysql控制台，首先删除原来的库。

mysql> drop database aaa;
Query OK, 1 row affected (0.21 sec)

要恢复数据库，必须先创建一个空的数据库，最好和以前库名保持一致。

mysql> create database aaa;
Query OK, 1 row affected (0.00 sec)

mysql> use aaa;
Database changed
mysql> source /home/admin/aaa.sql;
Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.02 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 4 rows affected (0.00 sec)
Records: 4  Duplicates: 0  Warnings: 0

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

mysql> select * from person;
+------+
| name |
+------+
| a    |
| A    |
| b    |
| B    |
+------+
4 rows in set (0.00 sec)

备份数据库中的表：

[root@localhost admin]# mysqldump -u root -p 数据库名 表名1 表名2 >./数据库名.bk

恢复数据库中的表

source 备份的路径/库名.bk;

注：如何查看当前文件存放路径(在终端下输入pwd命令即可查看)
6.修改库的字符集和校验规则：
示例：将 aaa 数据库的字符集改成 gbk

mysql> alter database aaa charset=gbk;
Query OK, 1 row affected (0.00 sec)

mysql> show create database aaa;
+----------+-------------------------------------------------------------+
| Database | Create Database                                             |
+----------+-------------------------------------------------------------+
| aaa      | CREATE DATABASE `aaa` /*!40100 DEFAULT CHARACTER SET gbk */ |
+----------+-------------------------------------------------------------+
1 row in set (0.00 sec)

将 aaa 数据库的校验规则改为utf8_general_ci

mysql> alter database aaa charset=utf8 collate utf8_general_ci;
Query OK, 1 row affected (0.00 sec)

三、表的操作
1.创建表

create table 表名(
列名1 类型1，
列名2 类型2，
...
)character set 字符集 collate 校验规则 engine 存储引擎;

说明：
character set字符集，若未指定字符集，则以所在数据库的字符集为准。
collate 校验规则，若未指定校验规则，则以所在数据库的校验规则为准。
创建一张表：

mysql> create table user(
    -> id int,
    -> name varchar(20),
    -> password char(32),
    -> birthday date)character set utf8 engine MYISAM;
Query OK, 0 rows affected (0.00 sec)

查看表结构

desc 表名;

例：

mysql> desc user;
+----------+-------------+------+-----+---------+-------+
| Field    | Type        | Null | Key | Default | Extra |
+----------+-------------+------+-----+---------+-------+
| id       | int(11)     | YES  |     | NULL    |       |
| name     | varchar(20) | YES  |     | NULL    |       |
| password | char(32)    | YES  |     | NULL    |       |
| birthday | date        | YES  |     | NULL    |       |
+----------+-------------+------+-----+---------+-------+
4 rows in set (0.00 sec)

2.修改表
(1)给表中添加一个字段

alter table 表名 add 字段名 类型;

示例：

mysql> alter table user add image varchar(50);
Query OK, 0 rows affected (0.01 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> desc user;
+----------+-------------+------+-----+---------+-------+
| Field    | Type        | Null | Key | Default | Extra |
+----------+-------------+------+-----+---------+-------+
| id       | int(11)     | YES  |     | NULL    |       |
| name     | varchar(20) | YES  |     | NULL    |       |
| password | char(32)    | YES  |     | NULL    |       |
| birthday | date        | YES  |     | NULL    |       |
| image    | varchar(50) | YES  |     | NULL    |       |
+----------+-------------+------+-----+---------+-------+
5 rows in set (0.00 sec)

(2)修改表中某个字段的长度

alter table 表名 modify 字段名 varchar(要求的长度);

示例：将user表中 name 的长度修改为60

mysql> alter table user modify name varchar(60);
Query OK, 0 rows affected (0.00 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> desc user;
+----------+-------------+------+-----+---------+-------+
| Field    | Type        | Null | Key | Default | Extra |
+----------+-------------+------+-----+---------+-------+
| id       | int(11)     | YES  |     | NULL    |       |
| name     | varchar(60) | YES  |     | NULL    |       |
| password | char(32)    | YES  |     | NULL    |       |
| birthday | date        | YES  |     | NULL    |       |
| image    | varchar(50) | YES  |     | NULL    |       |
+----------+-------------+------+-----+---------+-------+
5 rows in set (0.00 sec)

(3)删除表中某个字段

alter table 表名 drop 字段名;

(4)修改表名

alter table 表名 rename to 新表名;

(5)修改某一字段名

alter table 表名 change 原字段名 新字段名 类型;

例：

mysql> alter table user change image sex char(2);
Query OK, 0 rows affected (0.00 sec)
Records: 0  Duplicates: 0  Warnings: 0