三.SQL语句

[root@db01 ~]# mysqladmin -uroot -p123 ping

[root@db01 ~]# mysqladmin -uroot -p123 status

[root@db01 ~]# mysqladmin -uroot -p123 shutdown

[root@db01 ~]# mysqladmin -uroot -p123 variables

[root@db01 ~]# mysqladmin -uroot -p123 drop DATABASE

[root@db01 ~]# mysqladmin -uroot -p123 create DATABASE

[root@db01 ~]# mysqladmin -uroot -p123 reload

[root@db01 ~]# mysqladmin -uroot -p123 flush-log

[root@db01 ~]# mysqladmin -uroot -p123 reload

[root@db01 ~]# mysqladmin -uroot -p123 password

mysql> create database oldboy;

mysql> create database OLDBOY;

mysql> show databases;

mysql> show create database oldboy;

mysql> help create database

mysql> create database testa charset utf8;

mysql> drop database oldboy;

mysql> alter database oldboy charset gbk;

mysql> show create database oldboy;

mysql> create table student(
sid INT,
sname VARCHAR(20),
sage TINYINT,
sgender ENUM(‘m‘,‘f‘),
cometime DATETIME);

mysql> create table student(
sid INT NOT NULL PRIMARY KEY AUTO_INCREMENT COMMENT ‘学号’,
sname VARCHAR(20) NOT NULL COMMENT ‘学生姓名’,
sage TINYINT UNSIGNED COMMENT ‘学生年龄’,
sgender ENUM(‘m‘,‘f‘)  NOT NULL DEFAULT ‘m’ COMMENT ‘学生性别’,
cometime DATETIME NOT NULL COMMENT ‘入学时间’)chatset utf8 engine innodb;
#查看建表语句
mysql> show create table student;
#查看表
mysql> show tables;
#查看表中列的定义信息
mysql> desc student;

mysql> drop table student;

#修改表名
mysql> alter table student rename stu;
#添加列和列定义
mysql> alter table stu add age int;
#添加多个列
mysql> alter table stu add test varchar(20),add qq int;
#指定位置进行添加列（表首）
mysql> alter table stu add classid varchar(20) first;
#指定位置进行添加列（指定列）
mysql> alter table stu add phone int after age;
#删除指定的列及定义
mysql> alter table stu drop qq;
#修改列及定义（列属性）
mysql> alter table stu modify sid varchar(20);
#修改列及定义（列名及属性）
mysql> alter table stu change phone telphone char(20);

#授权root@10.0.0.51用户所有权限（非炒鸡管理员）
mysql> grant all on *.* to root@‘10.0.0.51‘ identified by ‘oldboy123‘;
#怎么去授权一个炒鸡管理员呢？
mysql> grant all on *.* to root@‘10.0.0.51‘ identified by ‘oldboy123‘ with grant option;
#其他参数（扩展）
max_queries_per_hour：一个用户每小时可发出的查询数量
max_updates_per_hour：一个用户每小时可发出的更新数量
max_connetions_per_hour：一个用户每小时可连接到服务器的次数
max_user_connetions：允许同时连接数量

#收回select权限
mysql> revoke select on *.* from root@‘10.0.0.51‘;
#查看权限
mysql> show grants for root@‘10.0.0.51‘;

#基础用法，插入数据
mysql> insert into stu values(‘linux01‘,1,NOW(),‘zhangsan‘,20,‘m‘,NOW(),110,123456);
#规范用法，插入数据
mysql> insert into stu(classid,birth.sname,sage,sgender,comtime,telnum,qq) values(‘linux01‘,1,NOW(),‘zhangsan‘,20,‘m‘,NOW(),110,123456);
#插入多条数据
mysql> insert into stu(classid,birth.sname,sage,sgender,comtime,telnum,qq) values(‘linux01‘,1,NOW(),‘zhangsan‘,20,‘m‘,NOW(),110,123456),
(‘linux02‘,2,NOW(),‘zhangsi‘,21,‘f‘,NOW(),111,1234567);

#不规范
mysql> update student set sgender=‘f‘;
#规范update修改
mysql> update student set sgender=‘f‘ where sid=1;
#如果非要全表修改
mysql> update student set sgender=‘f‘ where 1=1;

#不规范
mysql> delete from student;
#规范删除（危险）
mysql> delete from student where sid=3;
#DDL删除表
mysql> truncate table student;

1）额外添加一个状态列

mysql> alter table student add status enum(1,0) default 1;

2）使用update

mysql> update student set status=‘0‘ where sid=1;

3）应用查询存在的数据

mysql> select * from student where status=1;

#常用用法
mysql> select countrycode,district from city;
#查询单列
mysql> select countrycode from city;
#行级查询
mysql> select countrycode,district from city limit 2;
mysql> select id,countrycode,district from city limit 2,2;
#条件查询
mysql> select name,population from city where countrycode=‘CHN‘;
#多条件查询
mysql> select name,population from city where countrycode=‘CHN‘ and district=‘heilongjiang‘;
#模糊查询
mysql> select name,population,countrycode from city where countrycode like ‘%H%‘ limit 10;
#排序查询（顺序）
mysql> select id,name,population,countrycode from city order by countrycode limit 10;
#排序查询（倒叙）
mysql> select id,name,population,countrycode from city order by countrycode desc limit 10;
#范围查询(>,<,>=,<=,<>)
mysql> select * from city where population>=1410000;
#范围查询OR语句
mysql> select * from city where countrycode=‘CHN‘ or countrycode=‘USA‘;
#范围查询IN语句
mysql> select * from city where countrycode in (‘CHN‘,‘USA‘);