Mysql安装方式
MySQL安装方式有三种，一种是RPM方式安装，一种是源码编译安装，一种是通用二进制格式包安装。
RPM方式安装，可以直接使用yum命令安装或者下载RPM包后再安装
yum安装命令：
yum -y install mysql-server
系统会自动解决依赖关系，并将mysql客户端也安装上。
mysql交互模式中的命令类别：
客户端命令：在客户端执行的命令
服务器命令：在服务器上执行，并将结果返回给客户端。必须使用语句结束符，默认为封号“;”
MySQL数据库：
mysql安装完成后，默认有3个数据库
information_schema：是mysql运行过程中位于内存中的信息，保存mysql运行时数据，只有mysql启动时才有数据，平时是空的。
test：测试时才用到的数据库
mysql：mysql 的数据库
MySQL数据库目录：
[[email protected] ~]# ls /var/lib/mysql/ ibdata1 ib_logfile0 ib_logfile1 mysql mysql.sock test
可以看到没有information_schema数据库，因为它是存在内存中的。
MySQL常用命令：
DDL：定义数据库对象：
CREATE：
ALTER：
DROP：
DML：数据操纵语言
INSERT
UPDATE
DELETE
DCL数据控制语言
GRANT：
REVOKE：
创建数据库：
CREATE DATABASE db_name;
CREATE DATABASES IF NOT EXISTS testdb;
mysql> CREATE DATABASE test_db; Query OK, 1 row affected (0.00 sec) mysql> SHOW DATABASES; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | test | | test_db | +--------------------+ 4 rows in set (0.01 sec)
删除数据库：
DROP DATABASE db_name;
mysql> DROP DATABASE test_db; Query OK, 0 rows affected (0.00 sec) mysql> SHOW DATABASES; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | test | +--------------------+ 3 rows in set (0.00 sec)
创建表：
CREATE TABLE tb_name(col1,col2,...) col1,col2为字段名
注意：表是依赖于数据库的，所以在创建表之前，一定要指定默认数据库，使用命令
USER DATABASE; 来指定数据库
创建一个表，名为student，包含三个字段，Name、Age、Gender
mysql> CREATE TABLE students(Name CHAR(20) NOT NULL, Age TINYINT UNSIGNED,Gender CHAR(1) NOT NULL); Query OK, 0 rows affected (0.01 sec) mysql> SHOW TABLES; +-------------------+ | Tables_in_test_db | +-------------------+ | students | +-------------------+ 1 row in set (0.00 sec)
查看某个数据库中的表：
SHOW TABLES FROM db_name;
查看表结构：
DESC table_name;
mysql> DESC students; +--------+---------------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------+---------------------+------+-----+---------+-------+ | Name | char(20) | NO | | NULL | | | Age | tinyint(3) unsigned | YES | | NULL | | | Gender | char(1) | NO | | NULL | | +--------+---------------------+------+-----+---------+-------+ 3 rows in set (0.00 sec)
删除表：
DROP TABLE tb_name;
修改表：
ALTER TABLE tb_name;
MODIFY：修改某个字段，修改字段属性，字段名不改
CHANGE：改变某个字段，改变字段名称
ADD：添加字段
DROP：删除字段
可以通过help命令查询帮助信息：
help CREATE TABLE;
增加一个字段
例如：修改前面创建的student表，增加一个字段课程course,
mysql> ALTER TABLE students ADD course VARCHAR(100); Query OK, 0 rows affected (0.00 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> DESC students; +--------+---------------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------+---------------------+------+-----+---------+-------+ | Name | char(20) | NO | | NULL | | | Age | tinyint(3) unsigned | YES | | NULL | | | Gender | char(1) | NO | | NULL | | | course | varchar(100) | YES | | NULL | | +--------+---------------------+------+-----+---------+-------+ 4 rows in set (0.00 sec)
修改字段名称，例如将上面添加的course字段名改为Course
mysql> ALTER TABLE students CHANGE course Course VARCHAR(100); Query OK, 0 rows affected (0.00 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> DESC students; +--------+---------------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------+---------------------+------+-----+---------+-------+ | Name | char(20) | NO | | NULL | | | Age | tinyint(3) unsigned | YES | | NULL | | | Gender | char(1) | NO | | NULL | | | Course | varchar(100) | YES | | NULL | | +--------+---------------------+------+-----+---------+-------+ 4 rows in set (0.00 sec)
删除一个字段：
DROP col_name;
插入数据：
INSERT INTO tb_name (col1,col2,...) VALUES|VALUE (‘STRING‘,NUM...);
上面命令意思是：往某个表中插入数据，字段名为col1，col2,... 插入的值为字符串则，用引号引起来，如果为数值，则直接用数字。如果每一个字段都给值，则不用写字段名称
例如：在students表中插入两条数据，张三和李四
mysql> INSERT INTO students (Name,Gender) VALUE (‘ZhangSan‘,‘M‘),(‘LiSi‘,‘F‘);
Query OK, 2 rows affected (0.00 sec)
Records: 2 Duplicates: 0 Warnings: 0
查看数据
mysql> SELECT * FROM students; +----------+------+--------+--------+ | Name | Age | Gender | Course | +----------+------+--------+--------+ | ZhangSan | NULL | M | NULL | | LiSi | NULL | F | NULL | +----------+------+--------+--------+ 2 rows in set (0.01 sec)
插入一个用户，所有字段都有值：
注意，所有字段都有值，就不需要指定字段名
mysql> INSERT INTO students VALUES (‘ZengChengpeng‘,28,‘M‘,‘IT‘); Query OK, 1 row affected (0.00 sec) mysql> SELECT * FROM students WHERE Name=‘ZengChengpeng‘; +---------------+------+--------+--------+ | Name | Age | Gender | Course | +---------------+------+--------+--------+ | ZengChengpeng | 28 | M | IT | +---------------+------+--------+--------+ 1 row in set (0.00 sec)
修改数据：
UPDATE tb_name SET column=value WHERE 条件
例如：将ZengChengpeng的Course课程名称改为Develop
mysql> UPDATE students SET Course=‘Develop‘ WHERE Name=‘ZengChengpeng‘; Query OK, 1 row affected (0.00 sec) Rows matched: 1 Changed: 1 Warnings: 0 mysql> SELECT * FROM students WHERE Name=‘ZengChengpeng‘; +---------------+------+--------+---------+ | Name | Age | Gender | Course | +---------------+------+--------+---------+ | ZengChengpeng | 28 | M | Develop | +---------------+------+--------+---------+ 1 row in set (0.00 sec)
SELETE语句：
selete语句分为两种情况，
选择：指定以某字段作为搜索码，做逻辑比较，筛选符合条件的行。WHERE指定选择条件 投影：指定以某字段作为搜索码，做逻辑比较，筛选符合条件的字段。 mysql> SELECT Name,Course FROM students WHERE Gender=‘M‘; +---------------+---------+ | Name | Course | +---------------+---------+ | ZhangSan | NULL | | ZengChengpeng | Develop | +---------------+---------+
删除数据：
DELECT FROM tb_name WHERE 条件；
创建用户：
CREATE USER ‘USERNAME‘@‘HOST‘ IDENTIFIED BY ‘PASSWORD‘;
删除用户：
DROP USER ‘USERNAME‘@‘HOST‘;
HOST:
IP:
HOSTNAME:
NETWORK:
通配符: 通配符用引号引起来
_:下划线匹配任意单个字符：例如172.16.0._
%：匹配任意字符：
[email protected]‘%‘
用户权限：
添加权限：
GRANT pri1,pri2,... ON DB_NAME.TB_NAME TO ‘USERNAME‘@‘HOST‘ [IDENTIFIED BY ‘PASSWORD‘];
pri1 pri2表示权限名称，所有权限用ALL PRIVILEGES表示
取消权限：
REVOKE pri1，pri2,... ON DB_NAME.TB_NAME FROM ‘USERNAME‘@‘HOST‘;
创建用户示例：
mysql> CREATE USER ‘jerry‘@‘%‘ IDENTIFIED BY ‘jerry‘;
查看用户授权：
SHOW GRANTS FOR ‘USERNAME‘@‘HOST‘;
mysql> SHOW GRANTS FOR [email protected]‘%‘; +------------------------------------------------------------------------------------------------------+ | Grants for [email protected]% | +------------------------------------------------------------------------------------------------------+ | GRANT USAGE ON *.* TO ‘jerry‘@‘%‘ IDENTIFIED BY PASSWORD ‘*09FB9E6E2AA0750E9D8A8D22B6AA8D86C85BF3D0‘ | +------------------------------------------------------------------------------------------------------+
示例：给jerry用户test_db这个数据库所有表的所有权限
mysql> GRANT ALL PRIVILEGES ON test_db.* TO ‘jerry‘@‘%‘; Query OK, 0 rows affected (0.00 sec) mysql> SHOW GRANTS FOR ‘jerry‘@‘%‘; +------------------------------------------------------------------------------------------------------+ | Grants for [email protected]% | +------------------------------------------------------------------------------------------------------+ | GRANT USAGE ON *.* TO ‘jerry‘@‘%‘ IDENTIFIED BY PASSWORD ‘*09FB9E6E2AA0750E9D8A8D22B6AA8D86C85BF3D0‘ | | GRANT ALL PRIVILEGES ON `test_db`.* TO ‘jerry‘@‘%‘ | +------------------------------------------------------------------------------------------------------+ 2 rows in set (0.00 sec)
取消所有权限：
mysql> REVOKE ALL PRIVILEGES ON test_db.* FROM [email protected]‘%‘; Query OK, 0 rows affected (0.00 sec) mysql> SHOW GRANTS FOR ‘jerry‘@‘%‘; +------------------------------------------------------------------------------------------------------+ | Grants for [email protected]% | +------------------------------------------------------------------------------------------------------+ | GRANT USAGE ON *.* TO ‘jerry‘@‘%‘ IDENTIFIED BY PASSWORD ‘*09FB9E6E2AA0750E9D8A8D22B6AA8D86C85BF3D0‘ | +------------------------------------------------------------------------------------------------------+ 1 row in set (0.00 sec)