[python基础知识]those-mysql-must-be-the-basic-command-a那些MySQL必会的基础命令（一）
本文目录 [隐藏]
I. 那些MySQL必会的基础命令（一）
II. 启动与停止MySQL
单实例操作方法
第一种启动方式
[root@MySQL ~]# sed -i 's#/usr/local#/application#g' /application/mysql/bin/mysqld_safe
[root@MySQL ~]# /application/mysql/bin/mysqld_safe &
[1] 2869
[root@MySQL ~]# 150317 22:09:19 mysqld_safe Logging to '/application/mysql/data/MySQL.err'.
150317 22:09:19 mysqld_safe Starting mysqld daemon with databases from /application/mysql/data
[root@MySQL ~]# lsof -i :3306
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
mysqld 3085 mysql 10u IPv4 25607 0t0 TCP *:mysql (LISTEN)第二种启动方式
[root@MySQL ~]# cp /application/mysql/support-files/mysql.server /etc/init.d/mysqld
[root@MySQL ~]# vim /etc/init.d/mysqld
[root@MySQL ~]# sed -n 46,47p /etc/init.d/mysqld
basedir=/application/mysql/
datadir=/application/mysql/data/
[root@MySQL ~]# chmod +x /etc/init.d/mysqld
[root@MySQL ~]# /etc/init.d/mysqld start
Starting MySQL.. SUCCESS!
[root@MySQL ~]# lsof -i :3306
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
mysqld 3376 mysql 10u IPv4 26230 0t0 TCP *:mysql (LISTEN)
[root@MySQL ~]# chkconfig mysqld on多实例启动方式
第一种启动方式
[root@MySQL ~]# mysqld_safe --defaults-file=/data/3306/my.cnf &
[1] 7010
[root@MySQL ~]# 150317 22:22:46 mysqld_safe Logging to '/data/3306/mysql_oldboy3306.err'.
150317 22:22:46 mysqld_safe Starting mysqld daemon with databases from /data/3306/data
[root@MySQL ~]# lsof -i :3306
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
mysqld 7732 mysql 12u IPv4 16735 0t0 TCP *:mysql (LISTEN)第二种启动方式
[root@MySQL ~]# chmod +x /data/3306/mysql
[root@MySQL ~]# /data/3306/mysql start
Starting MySQL...
[root@MySQL ~]# lsof -i :3306
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
mysqld 6184 mysql 12u IPv4 15526 0t0 TCP *:mysql (LISTEN)MySQL关闭方式
第一种关闭方式
[root@MySQL ~]# /application/mysql/bin/mysqld_safe &
[1] 4417
[root@MySQL ~]# 150317 22:30:48 mysqld_safe Logging to '/application/mysql/data/MySQL.err'.
150317 22:30:48 mysqld_safe Starting mysqld daemon with databases from /application/mysql/data
[root@MySQL ~]# lsof -i :3306
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
mysqld 4633 mysql 10u IPv4 27506 0t0 TCP *:mysql (LISTEN)
[root@MySQL ~]# mysqladmin -uroot -p123456 shutdown
150317 22:30:55 mysqld_safe mysqld from pid file /application/mysql/data/MySQL.pid ended
[1]+ Done /application/mysql/bin/mysqld_safe
[root@MySQL ~]# lsof -i :3306第二种停止方式
[root@MySQL ~]# /etc/init.d/mysqld start
Starting MySQL.. SUCCESS!
[root@MySQL ~]# lsof -i :3306
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
mysqld 3664 mysql 10u IPv4 26620 0t0 TCP *:mysql (LISTEN)
[root@MySQL ~]# /etc/init.d/mysqld stop
Shutting down MySQL. SUCCESS!
[root@MySQL ~]# lsof -i :3306- 第三种停止方式
[root@MySQL ~]# lsof -i :3306
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
mysqld 3376 mysql 10u IPv4 26230 0t0 TCP *:mysql (LISTEN)
[root@MySQL ~]# pkill mysqld
[root@MySQL ~]# lsof -i :3306- 多实例关闭方式
[root@MySQL ~]# mysqld_safe --defaults-file=/data/3306/my.cnf &
[1] 7777
[root@MySQL ~]# 150317 22:38:14 mysqld_safe Logging to '/data/3306/mysql_oldboy3306.err'.
150317 22:38:14 mysqld_safe Starting mysqld daemon with databases from /data/3306/data
[root@MySQL ~]# mysqladmin -uroot -p3306 -S /data/3306/mysql.sock shutdown
150317 22:38:17 mysqld_safe mysqld from pid file /data/3306/mysqld.pid ended
[1]+ Done mysqld_safe --defaults-file=/data/3306/my.cnf
[root@MySQL ~]#
[root@MySQL ~]# lsof -i :3306III. MySQL登录方法
单实例登录
语法格式：
mysql –u[user] –p[password]
[root@MySQL ~]# mysql -uroot -p123456
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.5.32 MySQL Community Server (GPL)
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>单实例远程登录
语法格式：
mysql –u[user] –p[password] –h[hostname/ip]
[root@MySQL-Client ~]# mysql -uroot -p123456 -h10.10.10.100
[root@MySQL-Client ~]# mysql -uroot -p123456 -hmysql --也可以指定hostname方式链接
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 6
Server version: 5.5.32 MySQL Community Server (GPL)
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>多实例登录
语法格式：
mysql –u[user] –p[passwod] –S [sock path]
[root@MySQL ~]# mysql -uroot -p3306 -S /data/3306/mysql.sock
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 5
Server version: 5.5.32-log Source distribution
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>远程登录多实例
语法格式：
mysql –u[user] –p[passwod] –S [sock path] –P[port]
[root@MySQL ~]# mysql -uroot -p123456 -h10.10.10.10 -P3306
[root@MySQL ~]# mysql -uroot -p123456 -hMySQL -P3306 --也可以指定hostname方式链接
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 10
Server version: 5.5.32-log Source distribution
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>IV. 设置及更改MySQ root密码
没有密码设置密码
语法格式：
mysqladmin –u[user] password ‘[password]’
[root@MySQL ~]# /etc/init.d/mysqld start
Starting MySQL.. SUCCESS!
[root@MySQL ~]# mysql -uroot -p123456
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)
[root@MySQL ~]# mysqladmin -uroot password '123456'
[root@MySQL ~]# mysql -uroot -p123456
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.5.32 MySQL Community Server (GPL)
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>多实例没有密码设置密码
语法格式：
mysqladmin –u[user] password ‘[password]’ –S [sock path]
[root@MySQL ~]# /data/3307/mysql start
Starting MySQL...
[root@MySQL ~]# mysql -uroot -p123456 -S /data/3307/mysql.sock
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)
[root@MySQL ~]# mysqladmin -uroot password '123456' -S /data/3307/mysql.sock
[root@MySQL ~]# mysql -uroot -p123456 -S /data/3307/mysql.sock
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.5.32 Source distribution
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>有密码更改密码
语法格式：
mysqladmin –u[user] –p’[password]’password ‘[password]’
[root@MySQL ~]# mysqladmin -uroot -p'123456' password linux多实例有密码更改密码
语法格式：
mysqladmin –u[user] –p’[password]’password ‘[password]’ –S [sock path]
[root@MySQL ~]# mysqladmin -uroot -p'3306' password ‘123456’ -S /data/3306/mysql.sockSQL语句更改密码方式
mysql> update mysql.user set password=password("123456") where user='root';
mysql> flush privileges;单实例密码丢失更改密码
[root@MySQL ~]# /etc/init.d/mysqld stop
[root@MySQL ~]# mysqld_safe --skip-grant-tables --user=mysql &
[root@MySQL ~]# mysql
mysql> update mysql.user set password=password('123456') where user = 'root' and host = 'localhost';
mysql> flush privileges;
mysql> quit
[root@MySQL ~]# mysqladmin -uroot -p123456 shutdown
[root@MySQL ~]# /etc/init.d/mysqld start
[root@MySQL ~]# mysql -uroot -p123456多实例密码丢失更改密码
[root@MySQL ~]# killall mysqld
[root@MySQL ~]# mysqld_safe --defaults-file=/data/3310/my.cnf --skip-grant-table &
[root@MySQL ~]# mysql -uroot -p -S /data/3310/mysql.sock
mysql> update mysql.user set password=password('123456') where user = 'root' and host = 'localhost';
mysql> flush privileges;
mysql> quit
[root@MySQL ~]# /data/3310/mysql restart
[root@MySQL ~]# mysql -uroot -p123456 -S /data/3310/mysql.sockV. 数据库的备份与还原
[root@MySQL ~]# mysqldump -uroot -p123456 -S /data/3307/mysql.sock -B db >/root/msyql.bak-B和不加-B
[root@MySQL ~]# grep -vE "#|\/|^$|--" bak_b.sql
USE `oldboy`;
DROP TABLE IF EXISTS `student`;
CREATE TABLE `student` (
`id` int(4) NOT NULL AUTO_INCREMENT,
`name` char(20) NOT NULL,
`age` tinyint(2) NOT NULL DEFAULT '0',
`dept` varchar(16) DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `index_dept` (`dept`),
KEY `index_name` (`name`(8))
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
LOCK TABLES `student` WRITE;
UNLOCK TABLES;
DROP TABLE IF EXISTS `test`;
CREATE TABLE `test` (
`id` int(4) NOT NULL AUTO_INCREMENT,
`name` char(20) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;
LOCK TABLES `test` WRITE;
INSERT INTO `test` VALUES (1,'oldboy'),(2,'oldgirl'),(3,'inca'),(4,'zuma'),(5,'kaka');
UNLOCK TABLES;逻辑备份：
把数据库里的数据以SQL语句的方式导出来，然后还原的时候相当于执行了导出来的SQL的语句
恢复数据库
[root@mysql ~]# mysql -uroot -poldboy -S /data/3310/mysql.sock < bak_b.sqlVI. 创建与显示数据库
创建数据库
语法格式：
create dtabase [db_name];
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
+--------------------+
3 rows in set (0.00 sec)
mysql> create database db;
Query OK, 1 row affected (0.00 sec)
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| db |
| mysql |
| performance_schema |
+--------------------+
4 rows in set (0.00 sec)- 查看db库的字符集,默认你数据库是什么字符集，创建出来的库就是什么字符集，当然字符集也可以指定。
mysql> show create database db;
+----------+---------------------------------------------------------------+
| Database | Create Database |
+----------+---------------------------------------------------------------+
| db | CREATE DATABASE `db` /*!40100 DEFAULT CHARACTER SET latin1 */ |
+----------+---------------------------------------------------------------+
1 row in set (0.00 sec)创建指定字符集的数据库
- 创建GBK字符集数据库：
create database oldboy_gbk DEFAULT CHARACTER SET gbk COLLATE gbk_chinese_ci; - 创建UTF8数据库：
create database oldboy_utf8 CHARACTER SET utf8 COLLATE utf8_general_ci;- 创建一个名为db_gbk的GBK字符集数据库
mysql> create database db_gbk default character set gbk collate gbk_chinese_ci;
Query OK, 1 row affected (0.00 sec)- 查看一个库是什么字符集
语法格式：
show create database [db_name];
mysql> show create database db_gbk;
+----------+----------------------------------------------------------------+
| Database | Create Database |
+----------+----------------------------------------------------------------+
| db_gbk | CREATE DATABASE `db_gbk` /*!40100 DEFAULT CHARACTER SET gbk */ |
+----------+----------------------------------------------------------------+
1 row in set (0.00 sec)- 查看可以设定的字符集
mysql> 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 |
+----------+-----------------------------+---------------------+--------+
39 rows in set (0.00 sec)显示数据库
语法格式
show databases [db_name]
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| db |
| db_gbk |
| mysql |
| performance_schema |
+--------------------+
5 rows in set (0.00 sec)- 查看指定数据库
mysql> show databases like 'db';
+---------------+
| Database (db) |
+---------------+
| db |
+---------------+
1 row in set (0.00 sec)- 匹配查找
mysql> show databases like 'db%';
+----------------+
| Database (db%) |
+----------------+
| db |
| db_gbk |
+----------------+
2 rows in set (0.00 sec)显示数据库中的表
语法格式
show tables [db_name]
- 查看指定库存在的表
mysql> show tables from db;
Empty set (0.00 sec)- 查看当前库存在的表
mysql> use db
Database changed
mysql> show tables;
Empty set (0.00 sec)查看其他相关
- 显示当前所在数据库
mysql> select database();
+------------+
| database() |
+------------+
| NULL |
+------------+
1 row in set (0.00 sec)
mysql> use db
Database changed
mysql> select database();
+------------+
| database() |
+------------+
| db |
+------------+
1 row in set (0.00 sec)- 查看当前数据库版本
mysql> select version();
+-----------+
| version() |
+-----------+
| 5.5.32 |
+-----------+
1 row in set (0.00 sec)- 查看当前的用户
mysql> select user();
+----------------+
| user() |
+----------------+
| root@localhost |
+----------------+
1 row in set (0.00 sec)- 企业里怎么创建数据库呢？
- 根据开发的程序确定字符集（建议UTF8）
- 编译时候指定字符集，例如：
-DDEFAULT_CHARSET=utf8 \
-DDEFAULT_COLLATION=utf8_general_ci \
-DEXTRA_CHARSETS=gbk,gb2312,utf8,ascii \- 编译的时候没有指定字符集或者制定了和程序不同的字符集，如何解决？
指定字符集创建数据库即可。
create database oldboy_gbk DEFAULT CHARACTER SET gbk COLLATE gbk_chinese_ci; #创建GBK字符集数据库：
create database oldboy_utf8 CHARACTER SET utf8 COLLATE utf8_general_ci; #创建UTF8数据库VII. 删除库及表
删除库
语法格式
drop databases [db_name]
mysql> show databases like 'db';
+---------------+
| Database (db) |
+---------------+
| db |
+---------------+
1 row in set (0.00 sec)
mysql> drop database db;
Query OK, 0 rows affected (0.00 sec)
mysql> show databases like 'db';
Empty set (0.00 sec)VIII. 创建与删除用户
创建用户
语法格式
create user ‘[user]’@’[hostname]’ IDENTIFIED BY '[password]';
mysql> select user,host from mysql.user;
+------+-----------+
| user | host |
+------+-----------+
| root | 127.0.0.1 |
| root | localhost |
+------+-----------+
2 rows in set (0.00 sec)
mysql> create user 'db'@'localhost' identified by '123456';
Query OK, 0 rows affected (0.03 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> select user,host from mysql.user;
+------+-----------+
| user | host |
+------+-----------+
| root | 127.0.0.1 |
| db | localhost |
| root | localhost |
+------+-----------+
3 rows in set (0.00 sec)删除用户
语法格式
drop user ‘[user]’@’[hostame]’
mysql> select user,host from mysql.user;
+------+-----------+
| user | host |
+------+-----------+
| root | 127.0.0.1 |
| db | localhost |
| root | localhost |
+------+-----------+
3 rows in set (0.00 sec)
mysql> drop user 'db'@'localhost';
Query OK, 0 rows affected (0.00 sec)
mysql> select user,host from mysql.user;
+------+-----------+
| user | host |
+------+-----------+
| root | 127.0.0.1 |
| root | localhost |
+------+-----------+
2 rows in set (0.00 sec)SQL语句删除用户
如drop删除不了（一般是特殊字符或大写），可以用下面的方式删除
语法格式：
delete from mysql.usr where user = ‘[user]’ and host = ‘[hostname]’
mysql> select user,host from mysql.user;
+------+-----------+
| user | host |
+------+-----------+
| root | MySQL |
| root | localhost |
+------+-----------+
4 rows in set (0.00 sec)
mysql> drop user 'root'@'MySQL';
Query OK, 0 rows affected (0.00 sec)
mysql> select user,host from mysql.user;
+------+-----------+
| user | host |
+------+-----------+
| root | MySQL |
| root | localhost |
+------+-----------+
4 rows in set (0.00 sec)
mysql> delete from mysql.user where user = 'root' and host = 'MySQL';
Query OK, 1 row affected (0.00 sec)
mysql> select user,host from mysql.user;
+------+-----------+
| user | host |
+------+-----------+
| root | localhost |
+------+-----------+
3 rows in set (0.00 sec)IX. 数据库授权
查看用户被赋予的权限
语法格式
show grats for ‘[user]’@’[hostname]’;
mysql> show grants for 'db'@'localhost';
+-----------------------------------------------------------------------------------------------------------+
| Grants for db@localhost |
+-----------------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'db'@'localhost' IDENTIFIED BY PASSWORD '*6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9' |
| GRANT ALL PRIVILEGES ON `db`.* TO 'db'@'localhost' WITH GRANT OPTION |
+-----------------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)- 以不同的方式显示
mysql> show grants for 'db'@'localhost'\G;
*************************** 1. row ***************************
Grants for db@localhost: GRANT USAGE ON *.* TO 'db'@'localhost' IDENTIFIED BY PASSWORD '*6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9'
*************************** 2. row ***************************
Grants for db@localhost: GRANT ALL PRIVILEGES ON `db`.* TO 'db'@'localhost' WITH GRANT OPTION
2 rows in set (0.00 sec)添加用户授权
| grant | all | on dbname.* | to username@localhost | identified by 'passwd' |
|---|---|---|---|---|
| 授权命令 | 对应权限 | 目标：库和表 | 用户名和客户端主机 | 用户密码 |
语法格式
GRANT ALL ON db1.* TO 'jeffrey'@'localhost';
mysql> show grants for 'db'@'localhost';
+-----------------------------------------------------------------------------------------------------------+
| Grants for db@localhost |
+-----------------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'db'@'localhost' IDENTIFIED BY PASSWORD '*6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9' |
+-----------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
mysql> grant select on db.* to 'db'@'localhost';
Query OK, 0 rows affected (0.00 sec)
mysql> show grants for 'db'@'localhost';
+-----------------------------------------------------------------------------------------------------------+
| Grants for db@localhost |
+-----------------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'db'@'localhost' IDENTIFIED BY PASSWORD '*6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9' |
| GRANT SELECT ON `db`.* TO 'db'@'localhost' |
+-----------------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)移除用户权限
语法格式
revoke select on [db_name].[table_name] from '[user]'@'[hostname]';
mysql> show grants for 'db'@'localhost';
+-----------------------------------------------------------------------------------------------------------+
| Grants for db@localhost |
+-----------------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'db'@'localhost' IDENTIFIED BY PASSWORD '*6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9' |
| GRANT SELECT ON `db`.* TO 'db'@'localhost' |
+-----------------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)
mysql> revoke select on db.* from 'db'@'localhost';
Query OK, 0 rows affected (0.00 sec)
mysql> show grants for 'db'@'localhost';
+-----------------------------------------------------------------------------------------------------------+
| Grants for db@localhost |
+-----------------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'db'@'localhost' IDENTIFIED BY PASSWORD '*6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9' |
+-----------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)创建一个和root等价的管理员授权方法
grant all privileges on *.* to system@'localhost' identified by 'oldboy123' with grant option;
flush privileges;企业生产环境是如何授权用户权限？
- 博客，CMS等产品如何授权？
对于WEB连接也难怪乎授权尽量采用最小化原则，很多开源软件都是WEB界面安装，在安装期间除了select,insert,update,delete4个权限外，还需要create,drop等比较危险的权限
mysql> grant select,insert,update,delete,create,drop on blog.* to 'blog'@'localhost' identified by '123456';常规情况下授权select,insert,update,delete4个权限即可，有的开源软件，例如：discuz还需要create,drop的等比较危险的权限
- 生成数据库表后要收回create,drop授权
mysql> revoke create,drop on blog.* from 'blog'@'localhost';- 生产环境针对主库（写为主读为辅）用户的授权：
普通环境：
本机：LNMP,LAMP环境护具库授权
mysql> grant all privileges on blog.* to ‘blog’@’localhost’ identified by ‘123456’;应用服务器和数据库服务器不在一个主机上的授权
mysql> grant all privileges on blog.* to ‘blog’@’10.0.0.%’ identified by ‘123456’;严格的授权：重视安全，忽略了方便
mysql> grant select on blog.* to ‘blog’@’10.0.0.%’ identified by ‘123465’;- 生产环境从库（只读）用户的授权
mysql> grant select on blog.* to ‘blog’@’10.0.0.%’ identified by ‘123456’;说明：这里表示给10.0.0.0/24的用户blog管理blog数据库的所有表（*表示所有表）只读权限（select）,密码为123456
X. 表的相关操作
创建表
建表的基本命令语法： create table <表名> ( <字段名1> <类型1> , … <字段名n> <类型n>);
CREATE TABLE `test` (
`id` int(4) NOT NULL,
`name` char(20) NOT NULL,
`age` tinyint(2) NOT NULL DEFAULT '0',
`dept` varchar(16) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8 #创建时指定字符集索引类似文件系统的inode,记录类似文件系统的block,
索引要创建再where条件列上，而非要查询的内容列，才能加快查询速度
主键索引：类似身份证 唯一标示表内的一条记录
create table test(
id int(4) not null AUTO_INCREMENT,
name char(20) not null,
age tinyint(2) NOT NULL default '0',
dept varchar(16) default NULL,
primary key(id), #主键索引，记录唯一
KEY index_name (name) #普通索引，记录可能不唯一
);删除表
语法格式
drop tables [table_name]
mysql> show tables from db;
+--------------+
| Tables_in_db |
+--------------+
| test |
+--------------+
1 row in set (0.00 sec)
mysql> drop table test;
Query OK, 0 rows affected (0.01 sec)
mysql> show tables from db;
Empty set (0.00 sec)查看表的内容
命令语法：
select <字段1，字段2…> from <表名> where <表达式>
其中select fom where是不能随便改的
mysql> select * from oldboy.test;- 条件查询
mysql> select id,name from test whee name="ansheng";- 多个条件查询
mysql> select id,name from test where name='ansheng' or id=5;- 排序
mysql> select id,name from test order by id asc;
+----+---------+
| id | name |
+----+---------+
| 1 | oldboy |
| 2 | oldgirl |
| 3 | inca |
| 4 | zuma |
| 5 | kaka |
+----+---------+
5 rows in set (0.00 sec)
mysql> select id,name from test order by id desc;
+----+---------+
| id | name |
+----+---------+
| 5 | kaka |
| 4 | zuma |
| 3 | inca |
| 2 | oldgirl |
| 1 | oldboy |
+----+---------+
5 rows in set (0.00 sec)
mysql> select id,name from test where id >2 order by id desc;
+----+------+
| id | name |
+----+------+
| 5 | kaka |
| 4 | zuma |
| 3 | inca |
+----+------+
3 rows in set (0.00 sec)多表查询
mysql> select student.Sno,student.Sname,course.Cname,SC.Grade from student,course,SC where student.Sno=SC.Sno and course.Cno=SC.Cno order by student.Sname;查看表建立结构
mysql> desc student;
mysql> show columns from student;查看建立的表语句（可以看索引及创建表的相关信息）
mysql> show create table db.test\G
*************************** 1. row ***************************
Table: test
Create Table: CREATE TABLE `test` (
`id` int(4) NOT NULL,
`name` char(20) NOT NULL,
`age` tinyint(2) NOT NULL DEFAULT '0',
`dept` varchar(16) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8
1 row in set (0.00 sec)更改表名称
语法格式
rename table tb_name to new_tb_name
mysql> use db
Database changed
mysql> show tables;
+--------------+
| Tables_in_db |
+--------------+
| test |
+--------------+
1 row in set (0.00 sec)
mysql> rename table test to linux;
Query OK, 0 rows affected (0.08 sec)
mysql> show tables;
+--------------+
| Tables_in_db |
+--------------+
| linux |
+--------------+
1 row in set (0.00 sec)- 第二种改名方法
mysql> alter table kkk rename to test;往表里插入数据
按规矩指定所有列名，并且每列都插入值
语法格式
insert into tb_name(col_name) values(‘character’);
mysql> insert into test(id,name) values(1,'natasha');
Query OK, 1 row affected (0.00 sec)
mysql> select * from test;
+----+---------+-----+------+
| id | name | age | dept |
+----+---------+-----+------+
| 1 | natasha | 0 | NULL |
+----+---------+-----+------+
1 row in set (0.00 sec)由于ID列为自增的，所以，可以只在name列插入值
mysql> insert into test(name) values('harry');
Query OK, 1 row affected, 1 warning (0.00 sec)
mysql> select * from test;
+----+---------+-----+------+
| id | name | age | dept |
+----+---------+-----+------+
| 1 | natasha | 0 | NULL |
| 0 | harry | 0 | NULL |
+----+---------+-----+------+
2 rows in set (0.00 sec)如果不指定列，就要按规矩为每列都插入恰当的值
insert into test values(3,’inca’)批量插入数据方法
insert into test values(4,'zuma'),(5,'kaka');
insert into `test` VALUES (1,'oldboy'),(2,'oldgirl'),(3,'inca'),(4,'zuma'),(5,'kaka');删除表中的数据
- 清空表内容
mysql> truncate table test;
mysql> delete from test;- 删除字段：
mysql> ALTER TABLE table_name DROP field_name;