mysql基础命令讲解
mysql基础命令讲解
1、启动与关闭mysql
方法一：
启动 : /etc/init.d/mysqld start
关闭：/etc/init.d/mysqld stop
提示：/etc/init.d/mysqld 由/home/zhangjie/tool/mysql-5.1.62/support-files/mysql-server复制而来。
方法二：
启动：/usr/local/mysql/bin/mysqld_safe --user=mysql &
关闭：killall mysqld
2、mysql登录
无密码登录：mysql直接回车进入
有密码登录：mysql -u root -p回车。输入正确的密码登录或 mysql -uroot -p'123456'回车。
提示：这里的123456是mysql的密码，有一个弊端就是是明文,很容易让人通过history查到
3、退出mysql
方法一：exit
方法二：quit
4、设置修改mysql root 用户密码
由于安装mysql后，默认管理员root密码为空，这很不安全，因此需要修改
mysqladmin -u root password '123456'
修改root密码
方法一：
mysqladmin -u root -p'123456' password '654321'
注：-p'123456'中间无空格 password '654321'中间是有空格的
方法二：
>mysql UPDATE mysql.user SET password=PASSWORD("123456") WHERE user='root'
>mysql flush privileges
5、如何找回丢失的mysql root用户登录密码
单实例：
killall mysqld
mysqld_safe --skip-grant-tables &
mysql -u root -p直接回车不要密码
修改密码：
>mysql UPDATE mysql.user SET password=PASSWORD("zhangjie") WHERE user='root'
>mysql flush privileges;
注：这里不能使用mysqladmin修改，只能无密码进入mysql后再通过 UPDATE更改密码
多实例：
6、创建一个数据库
创建一个默认的数据库： >mysql create database zhangjie_default;
创建一个字符级为gbk的数据库：>mysql create database zhangjie_gbk DEFAULT CHARACTER SET gbk COLLATE gbk_chinese_ci;
创建一个字符级为utf8的数据库: >mysql create database zhangjie_utf8 DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci;
7、查看数据库
>mysql show create database zhangjie_default;
8、显示所有的数据库
>mysql show databases;
查看单个数据库
>mysql show databases like 'blog_utf8';
9、连接数据库
>mysql use blog_gbk;
查看我当前的数据库
>mysql select database();
查看mysql的版本
>mysql select version();
查看我当前所使用的用户
>mysql select user();
查看当前数据库包含的表信息
>mysql show tables;
10、 查看当前数据库中所有的用户有哪些
>mysql select user,host from mysql.user;
11、查看用户的权限
>mysql show grants for root@localhost;
12、删除系统多余帐号
>mysql drop user 'root'@'localhost'
13、创建用户并授予权限
>mysql GRANT ALL on *.* TO 'blog'@'10.0.0.%' identified by '123456'
生产环境下主库用户的授权
>mysql GRANT SELECT,INSERT,UPDATE,DELETE on blog.* TO 'blog'@'10.0.0.%' identified by '123456'
生立环境下从库用户的授权
>mysql GRANT SELECT ON blog.* TO 'blog'@'10.0.0.%' identified by '123456'
14、建表操作
mysql> create table test(id int(4) not null primary key auto_increment,name char(20)not null);
Query OK, 0 rows affected (0.04 sec)
查看表
mysql> show tables;
+---------------------+
| Tables_in_blog_utf8 |
+---------------------+
| test |
+---------------------+
1 row in set (0.00 sec)
查看表结构
mysql> desc test;
+-------+----------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------+----------+------+-----+---------+----------------+
| id | int(4) | NO | PRI | NULL | auto_increment |
| name | char(20) | NO | | NULL | |
+-------+----------+------+-----+---------+----------------+
2 rows in set (0.01 sec)
mysql> show columns from test;
+-------+----------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------+----------+------+-----+---------+----------------+
| id | int(4) | NO | PRI | NULL | auto_increment |
| name | char(20) | NO | | NULL | |
+-------+----------+------+-----+---------+----------------+
2 rows in set (0.00 sec)
查建表语句
mysql> show create table test \G;
*************************** 1. row ***************************
Table: test
Create Table: CREATE TABLE `test` (
`id` int(4) NOT NULL AUTO_INCREMENT,
`name` char(20) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8
1 row in set (0.00 sec)
ERROR:
No query specified
注：mysql默认的引擎是MyISAM引擎
15、插入数据
mysql> insert into test(id,name) values(1,'zhangjie');
Query OK, 1 row affected (0.00 sec)
mysql> select * from test;
+----+----------+
| id | name |
+----+----------+
| 1 | zhangjie |
+----+----------+
1 row in set (0.00 sec)
mysql> insert into test(name) values('botian');
Query OK, 1 row affected (0.00 sec)
mysql> select * from test;
+----+----------+
| id | name |
+----+----------+
| 1 | zhangjie |
| 2 | botian |
+----+----------+
2 rows in set (0.00 sec)
mysql> insert into test(name) values('lubeijian');
Query OK, 1 row affected (0.01 sec)
mysql> select * from test;
+----+-----------+
| id | name |
+----+-----------+
| 1 | zhangjie |
| 2 | botian |
| 3 | lubeijian |
+----+-----------+
3 rows in set (0.01 sec)
mysql> insert into test values(4,'elain'),(5,'wodi');
Query OK, 2 rows affected (0.00 sec)
Records: 2 Duplicates: 0 Warnings: 0
mysql> select * from test;
+----+-----------+
| id | name |
+----+-----------+
| 1 | zhangjie |
| 2 | botian |
| 3 | lubeijian |
| 4 | elain |
| 5 | wodi |
+----+-----------+
5 rows in set (0.00 sec)
mysql> insert into test(name) values('A'),('B'),('C');
Query OK, 3 rows affected (0.00 sec)
Records: 3 Duplicates: 0 Warnings: 0
mysql> select * from test;
+----+-----------+
| id | name |
+----+-----------+
| 1 | zhangjie |
| 2 | botian |
| 3 | lubeijian |
| 4 | elain |
| 5 | wodi |
| 6 | A |
| 7 | B |
| 8 | C |
+----+-----------+
8 rows in set (0.00 sec)
16、备份数据库
mysql> system mysqldump -u root -p'123456' -A -B >/tmp/zhangjiebak.sq
17、查看表中的内容
mysql> select * from test limit 2;
+----+----------+
| id | name |
+----+----------+
| 1 | zhangjie |
| 2 | botian |
+----+----------+
2 rows in set (0.00 sec)
mysql> select * from test limit 3;
+----+-----------+
| id | name |
+----+-----------+
| 1 | zhangjie |
| 2 | botian |
| 3 | lubeijian |
+----+-----------+
3 rows in set (0.00 sec)
mysql> select * from test limit 0,4;
+----+-----------+
| id | name |
+----+-----------+
| 1 | zhangjie |
| 2 | botian |
| 3 | lubeijian |
| 4 | elain |
+----+-----------+
4 rows in set (0.00 sec)
mysql> select * from test where id > 6;
+----+------+
| id | name |
+----+------+
| 7 | B |
| 8 | C |
+----+------+
2 rows in set (0.00 sec)
mysql> select * from test where id < 4;
+----+-----------+
| id | name |
+----+-----------+
| 1 | zhangjie |
| 2 | botian |
| 3 | lubeijian |
+----+-----------+
3 rows in set (0.00 sec)
mysql> select * from test where name='zhangjie';
+----+----------+
| id | name |
+----+----------+
| 1 | zhangjie |
+----+----------+
1 row in set (0.00 sec)
18、修改表中的数据
先查一下表中的内容
mysql> select * from test;
+----+-----------+
| id | name |
+----+-----------+
| 1 | zhangjie |
| 2 | botian |
| 3 | lubeijian |
| 4 | elain |
| 5 | wodi |
| 6 | A |
| 7 | B |
| 8 | C |
+----+-----------+
8 rows in set (0.00 sec)
将id=1的这一行中name改为oldboy，原来为zhangjie
mysql> update test set name='oldboy'where id=1;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0
再查一下表中的内容，发现已经改过来了
mysql> select * from test;
+----+-----------+
| id | name |
+----+-----------+
| 1 | oldboy |
| 2 | botian |
| 3 | lubeijian |
| 4 | elain |
| 5 | wodi |
| 6 | A |
| 7 | B |
| 8 | C |
+----+-----------+
8 rows in set (0.00 sec)
19、删除表中的数据
先查看一下表中的内容
mysql> select * from test;
+----+-----------+
| id | name |
+----+-----------+
| 2 | botian |
| 3 | lubeijian |
| 4 | elain |
| 5 | wodi |
| 6 | A |
| 7 | B |
| 8 | C |
+----+-----------+
7 rows in set (0.01 sec)
删除id < 5的内容
mysql> delete from test where id < 5;
Query OK, 3 rows affected (0.01 sec)
再量一下表中id < 5的都已经没有了
mysql> select * from test;
+----+------+
| id | name |
+----+------+
| 5 | wodi |
| 6 | A |
| 7 | B |
| 8 | C |
+----+------+
4 rows in set (0.00 sec)
删除整个test表
mysql> truncate table test;
Query OK, 0 rows affected (0.00 sec)
mysql> select * from test;
Empty set (0.00 sec)
19、在表中增加字段（dba操作）
mysql> alter table test add sex char(4);
Query OK, 0 rows affected (0.01 sec)
Records: 0 Duplicates: 0 Warnings: 0
查看表中内容
mysql> desc test;
+-------+----------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------+----------+------+-----+---------+----------------+
| id | int(4) | NO | PRI | NULL | auto_increment |
| name | char(20) | NO | | NULL | |
| sex | char(4) | YES | | NULL | |
+-------+----------+------+-----+---------+----------------+
3 rows in set (0.01 sec)
在name之后添加一个age字段
mysql> alter table test add age int(4) after name;
Query OK, 0 rows affected (0.01 sec)
Records: 0 Duplicates: 0 Warnings: 0
查看表中内容
mysql> desc test;
+-------+----------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------+----------+------+-----+---------+----------------+
| id | int(4) | NO | PRI | NULL | auto_increment |
| name | char(20) | NO | | NULL | |
| age | int(4) | YES | | NULL | |
| sex | char(4) | YES | | NULL | |
+-------+----------+------+-----+---------+----------------+
4 rows in set (0.00 sec)
20、删除表中的内容
删除前查看表中内容
mysql> desc test;
+-------+----------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------+----------+------+-----+---------+----------------+
| id | int(4) | NO | PRI | NULL | auto_increment |
| name | char(20) | NO | | NULL | |
| age | int(4) | YES | | NULL | |
| sex | char(4) | YES | | NULL | |
+-------+----------+------+-----+---------+----------------+
4 rows in set (0.00 sec)
删除表中sex 这一列内容
mysql> alter table test drop sex;
Query OK, 0 rows affected (0.05 sec)
Records: 0 Duplicates: 0 Warnings: 0
再次查看验证
mysql> desc test;
+-------+----------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------+----------+------+-----+---------+----------------+
| id | int(4) | NO | PRI | NULL | auto_increment |
| name | char(20) | NO | | NULL | |
| age | int(4) | YES | | NULL | |
+-------+----------+------+-----+---------+----------------+
3 rows in set (0.00 sec)
21、更改表名
先查看表名
mysql> show tables;
+---------------------+
| Tables_in_blog_utf8 |
+---------------------+
| test |
+---------------------+
1 row in set (0.00 sec)
使用rename修改表名
mysql> rename table test to zhangjietest;
Query OK, 0 rows affected (0.00 sec)
再次查看修改后的表名
mysql> show tables;
+---------------------+
| Tables_in_blog_utf8 |
+---------------------+
| zhangjietest |
+---------------------+
1 row in set (0.00 sec)
使用 alter 修改表名
mysql> alter table zhangjietest rename to zhangjie;
Query OK, 0 rows affected (0.01 sec)
查看是否修改成功
mysql> show tables;
+---------------------+
| Tables_in_blog_utf8 |
+---------------------+
| zhangjie |
+---------------------+
1 row in set (0.00 sec)
22、删除整张表
先查看都有哪些表
mysql> show tables;
+---------------------+
| Tables_in_blog_utf8 |
+---------------------+
| zhangjie |
+---------------------+
1 row in set (0.00 sec)
删除名为zhangjie的表
mysql> drop table zhangjie;
Query OK, 0 rows affected (0.01 sec)
再次查看都有哪些表，这里显示这个库里面已经没有表了，空了
mysql> show tables;
Empty set (0.00 sec)