centOS7安装mysql及使用

$ sudo rpm -ivh mysql-community-release-el7-5.noarch.rpm

安装mysql时网上搜索了很多种方法，总是出现各种问题，总结了一种比较简单的，能用，但是不知道靠不靠谱。

提示：我使用root登录的系统，其他账户不确定能不能用。

1.下载mysql的repo源

$ wget http://repo.mysql.com/mysql-community-release-el7-5.noarch.rpm

2.安装mysql-community-release-el7-5.noarch.rpm包

$ sudo rpm -ivh mysql-community-release-el7-5.noarch.rpm

3.安装mysql

$ sudo yum install mysql-server

根据提示安装就可以了,不过安装完成后没有密码,需要重置密码


4.重置mysql密码


$ mysql -u root


登录时有可能报这样的错：ERROR 2002 (HY000): Can‘t connect to local MySQL server through socket ‘/var/lib/mysql/mysql.sock‘ (2)，原因是/var/lib/mysql的访问权限问题。下面的命令把/var/lib/mysql的拥有者改为当前用户：


$ sudo chown -R root:root /var/lib/mysql


重启mysql服务


$ service mysqld restart


接下来登录重置密码：


$ mysql -u root 
mysql > use mysql;
mysql > update user set password=password('123456') where user='root';

mysql > exit;

mysqlf服务安装完成。下面介绍初次进入数据库及使用。

1打开mysqld

service mysqld start

2.登录

mysql -u -p

3.可以为所欲为了

1.6.2 常用命令创建一个数据库：mysql> create database [databasename];列出所有数据库：mysql> show databases;切换到一个数据库：mysql> use [db name];显示一个数据库的所有表：mysql> show tables;查看数据表的字段格式：mysql> describe [table name];删除一个数据库：mysql> drop database [database name];删除一个数据表：mysql> drop table [table name];显示一个数据表的所有数据：mysql> SELECT * FROM [table name];返回指定数据表的各列信息：mysql> show columns from [table name];使用值“whatever”过滤显示选定的某些行：mysql> SELECT * FROM [table name] WHERE [field name] = "whatever";显示所有包含name为”Bob”和phone number为“3444444”的记录：mysql> SELECT * FROM [table name] WHERE name = "Bob" AND phone_number = '3444444';显示所有不包含name为”Bob”和phone number为“3444444”的记录，并以phone_number字段排序：mysql> SELECT * FROM [table name] WHERE name != "Bob" AND phone_number = '3444444' order by phone_number;显示所有的name以字母“bob”开头和phone number为“3444444”的记录：mysql> SELECT * FROM [table name] WHERE name like "Bob%" AND phone_number = '3444444';显示name以字母“bob”开头和phone number为“3444444”的第1至第5条记录：mysql> SELECT * FROM [table name] WHERE name like "Bob%" AND phone_number = '3444444' limit 1,5;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";返回唯一不同的记录：mysql> SELECT DISTINCT [column name] FROM [table name];以升序或降序显示选定的记录：mysql> SELECT [col1],[col2] FROM [table name] ORDER BY [col2] DESC;返回行数：mysql> SELECT COUNT(*) FROM [table name];统计指定列值的总和：mysql> SELECT SUM(*) FROM [table name];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;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 -pmysql> use mysql;mysql> INSERT INTO user (Host,User,Password) VALUES('%','username',PASSWORD('password'));mysql> flush privileges;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 rootmysql> 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 startroot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 -pmysql> 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 -pmysql> 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;更新已存在表的数据：mysql> UPDATE [table name] SET Select_priv = 'Y',Insert_priv = 'Y',Update_priv = 'Y' where [field name] = 'user';删除表中[field name] = ‘whatever’的行：mysql> DELETE from [table name] where [field name] = 'whatever';更新数据库的权限/特权：mysql> flush privileges;删除列：mysql> alter table [table name] drop column [column name];新增列到db：mysql> alter table [table name] add column [new column name] varchar (20);更改列名：mysql> alter table [table name] change [old column name] [new column name] varchar (50);增加唯一的列：mysql> alter table [table name] add unique ([column name]);设置列值大点：mysql> alter table [table name] modify [column name] VARCHAR(3);删除唯一列：mysql> alter table [table name] drop index [colmn name];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);导出所有数据库到sql文件：# [mysql dir]/bin/mysqldump -u root -ppassword --opt >/tmp/alldatabases.sql导出一个数据库：# [mysql dir]/bin/mysqldump -u username -ppassword --databases databasename >/tmp/databasename.sql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从sql文件还原数据库（数据表）：# [mysql dir]/bin/mysql -u username -ppassword databasename < /tmp/databasename.sql创建数据表例1：mysql> CREATE TABLE [table name] (firstname VARCHAR(20), middleinitial VARCHAR(3), lastname VARCHAR(35),suffix VARCHAR(3),officeid VARCHAR(10),userid VARCHAR(15),username VARCHAR(8),email VARCHAR(35),phone VARCHAR(25), groups VARCHAR(15),datestamp DATE,timestamp time,pgpemail VARCHAR(255));创建数据表例2：mysql> create table [table name] (personid int(50) not null auto_increment primary key,firstname varchar(35),middlename varchar(50),lastnamevarchar(50) default 'bato');