linux下操作数据库

通过命令行操作数据库：

1.启动数据库系统：/etc/rc.d/init.d/mysql start;

2.连接数据库：mysql -u用户名 -p 密码;

3.退出数据库:mysql>quit;

4.创建一个数据库：mysql> create database [databasename];

5.列出所有数据库：mysql> show databases;

6.切换到一个数据库：mysql> use [db name];

7.找出当然选择了哪个数据库：mysql>show database();

8.显示一个数据库的所有表：mysql> show tables;

9.查看数据表的字段格式：mysql> describe [table name];

10.删除一个数据库：mysql> drop database [database name];

11.删除一个数据表：mysql> drop table [table name];

12.创建表：mysql>create table [tablename](id int not null,name varchar(20));

13.显示一个数据表的所有数据：mysql> SELECT * FROM [table name];

14.返回指定数据表的各列信息：mysql> show columns from [table name];

15.使用值“whatever”过滤显示选定的某些行：mysql> SELECT * FROM [table name] WHERE [field name] = "whatever";

16.使用正则表达式查找记录：使用“正则表达式二进制”强制区分大小写：此命令查找以a开头的任何记录：mysql> SELECT * FROM [table name] WHERE rec RLIKE "^a";

17.返回唯一不同的记录：mysql> SELECT DISTINCT [column name] FROM [table name];

18.以升序或降序显示选定的记录：mysql> SELECT [col1],[col2] FROM [table name] ORDER BY [col2] DESC;

19.返回行数：mysql> SELECT COUNT(*) FROM [table name];

20.统计指定列值的总和：mysql> SELECT SUM(*) FROM [table name];

21.插入数据：mysql>insert into [tablename] values( 2,"xiaoyanger" );

22.更新数据：update [tablename] set id=3,name=" ";

23.联结表：mysql> select lookup.illustrationid, lookup.personid,person.birthday from lookup left join person on lookup.personid=person.personid=statement to join birthday in person table with primary illustration id;

24.新建一个用户：以root登录：切换到mysql数据库，创建用户，刷新权限：

# mysql -u root -p

mysql> use mysql;

mysql> INSERT INTO user (Host,User,Password) VALUES('%','username',PASSWORD('password'));

mysql> flush privileges;

25.删除表中行：mysql> DELETE from [table name] where [field name] = 'whatever';

26.更新数据库的权限/特权：mysql> flush privileges;

27.删除列：mysql> alter table [table name] drop column [column name];

28.新增列到db：mysql> alter table [table name] add column [new column name] varchar (20);

29.更改列名：mysql> alter table [table name] change [old column name] [new column name] varchar (50);

30.增加唯一的列：mysql> alter table [table name] add unique ([column name]);

31.设置列值大点：mysql> alter table [table name] modify [column name] VARCHAR(3);

32.删除唯一列：mysql> alter table [table name] drop index [colmn name];

33.导入一个CSV文件到表：mysql> LOAD DATA INFILE '/tmp/filename.csv' replace INTO TABLE [table name] FIELDS TERMINATED BY ',' LINES TERMINATED BY '\n' (field1,field2,field3);

34.导出所有数据库到sql文件：# [mysql dir]/bin/mysqldump -u root -ppassword --opt >/tmp/alldatabases.sql

35.导出一个数据库：# [mysql dir]/bin/mysqldump -u username -ppassword --databases databasename >/tmp/databasename.sql

36.从一个数据库导出一个表：# [mysql dir]/bin/mysqldump -c -u username -ppassword databasename tablename > /tmp/databasename.tablename.sql

37.从sql文件还原数据库（数据表）：# [mysql dir]/bin/mysql -u username -ppassword databasename < /tmp/databasename.sql

38.从unix命令行更改用户密码：

# [mysql dir]/bin/mysqladmin -u username -h hostname.blah.org -p password 'new-password'

从mysql命令行更改用户密码：以root登录，设置密码，更新权限：

# /etc/init.d/mysql stop

# mysqld_safe --skip-grant-tables &

# mysql -u root

mysql> use mysql;

mysql> update user set password=PASSWORD("newrootpassword") where User='root';

mysql> flush privileges;

mysql> quit

# /etc/init.d/mysql stop

# /etc/init.d/mysql start

root密码为空时，设置root密码：

# mysqladmin -u root password newpassword

更新root密码：

# mysqladmin -u root -p oldpassword newpassword

允许用户“bob”从localhost以密码“passwd”连接服务器：以root登录，切换mysql数据库：设置权限，更新权限：

# mysql -u root -p

mysql> use mysql;

mysql> grant usage on *.* to bob@localhost identified by 'passwd';

mysql> flush privileges;

为数据库db设置权限：以root登录，切换到mysql数据库，授予权限，更新权限：

# mysql -u root -p

mysql> use mysql;

mysql> INSERT INTO db (Host,Db,User,Select_priv,Insert_priv,Update_priv,Delete_priv,Create_priv,Drop_priv) VALUES ('%','databasename','username','Y','Y','Y','Y','Y','N');

mysql> flush privileges;

或者

mysql> grant all privileges on databasename.* to username@localhost;

mysql> flush privileges;