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：
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[root@host2 ~]
# ls /var/lib/mysql/
ibdata1 ib_logfile0 ib_logfile1 mysql mysql.sock
test
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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;
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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)
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删除数据库：
DROP DATABASE db_name;
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mysql> DROP DATABASE test_db;
Query OK, 0 rows affected (0.00 sec)
mysql> SHOW DATABASES;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
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test
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+--------------------+
3 rows
in
set
(0.00 sec)
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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
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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)
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查看某个数据库中的表：
SHOW TABLES FROM db_name;
查看表结构：
DESC table_name;
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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)
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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,
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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)
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修改字段名称，例如将上面添加的course字段名改为Course
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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)
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删除一个字段：
DROP col_name;
插入数据：
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INSERT INTO tb_name (col1,col2,...) VALUES|VALUE (
'STRING'
,NUM...);
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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
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mysql> SELECT * FROM students;
+----------+------+--------+--------+
| Name | Age | Gender | Course |
+----------+------+--------+--------+
| ZhangSan | NULL | M | NULL |
| LiSi | NULL | F | NULL |
+----------+------+--------+--------+
2 rows
in
set
(0.01 sec)
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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
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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)
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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
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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)
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SELETE语句：
selete语句分为两种情况，
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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 |
+---------------+---------+
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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：
jerry@'%'
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：
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mysql> CREATE USER
'jerry'
@
'%'
IDENTIFIED BY
'jerry'
;
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查看用户授权：
SHOW GRANTS FOR 'USERNAME'@'HOST';
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mysql> SHOW GRANTS FOR jerry@
'%'
;
+------------------------------------------------------------------------------------------------------+
| Grants
for
jerry@% |
+------------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO
'jerry'
@
'%'
IDENTIFIED BY PASSWORD
'*09FB9E6E2AA0750E9D8A8D22B6AA8D86C85BF3D0'
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+------------------------------------------------------------------------------------------------------+
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示例：给jerry用户test_db这个数据库所有表的所有权限
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mysql> GRANT ALL PRIVILEGES ON test_db.* TO
'jerry'
@
'%'
;
Query OK, 0 rows affected (0.00 sec)
mysql> SHOW GRANTS FOR
'jerry'
@
'%'
;
+------------------------------------------------------------------------------------------------------+
| Grants
for
jerry@% |
+------------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO
'jerry'
@
'%'
IDENTIFIED BY PASSWORD
'*09FB9E6E2AA0750E9D8A8D22B6AA8D86C85BF3D0'
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| GRANT ALL PRIVILEGES ON `test_db`.* TO
'jerry'
@
'%'
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+------------------------------------------------------------------------------------------------------+
2 rows
in
set
(0.00 sec)
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取消所有权限：
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mysql> REVOKE ALL PRIVILEGES ON test_db.* FROM jerry@
'%'
;
Query OK, 0 rows affected (0.00 sec)
mysql> SHOW GRANTS FOR
'jerry'
@
'%'
;
+------------------------------------------------------------------------------------------------------+
| Grants
for
jerry@% |
+------------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO
'jerry'
@
'%'
IDENTIFIED BY PASSWORD
'*09FB9E6E2AA0750E9D8A8D22B6AA8D86C85BF3D0'
|
+------------------------------------------------------------------------------------------------------+
1 row
in
set
(0.00 sec)
|
