主键
代码语言：javascript复制-- 为当前表添加主键
ALTER TABLE `tablename`
ADD COLUMN id TINYINT UNSIGNED NOT NULL AUTO_INCREMENT,
ADD PRIMARY KEY (id);
-- 删除主键
ALTER TABLE `tablename`
DROP PRIMARY KEY;创建数据库
代码语言：javascript复制# utf8mb4_unicode_ci更准
CREATE DATABASE IF NOT EXISTS typecho DEFAULT CHARSET utf8mb4 COLLATE utf8mb4_unicode_ci;
# utf8mb4_general_ci更快
CREATE DATABASE IF NOT EXISTS typecho DEFAULT CHARSET utf8mb4 COLLATE utf8mb4_general_ci;
CREATE DATABASE typecho DEFAULT CHARACTER SET gbk COLLATE gbk_chinese_ci;创建用户并提供相应权限
代码语言：javascript复制# 只是创建用户
CREATE USER phpergao@'localhost' IDENTIFIED BY 'yourpasswd';
# 赋予权限
GRANT select,update on phpergao.* to phpergao@'localhost';
GRANT index ON phpergao.* TO phpergao@'192.168.0.%';
# 创建用户并赋予权限
GRANT ALL PRIVILEGES ON phpergao.* TO 'phpergao'@'localhost' IDENTIFIED BY 'yourpasswd';
# 相反的revoke 跟 grant 的语法差不多，只需要把关键字 “to” 换成 “from” 即可：
REVOKE ALL PRIVILEGES ON phpergao.* FROM 'phpergao'@'localhost';
# ALL PRIVILEGES 可以换为select,insert,update,delete,create,drop,index,alter,grant,references,reload,shutdown,process,file等14个权限。
# 删除用户
DELETE FROM user WHERE User='phpergao' and Host='localhost';
# 修改用户密码
UPDATE USER SET PASSWORD = PASSWORD ('newpasswd') WHERE USER = 'phpergao' AND HOST = 'localhost';刷新权限
代码语言：javascript复制FLUSH PRIVILEGES;查看用户权限
代码语言：javascript复制# 查看自己的权限
SHOW GRANTS;
# 查看其他人的权限
SHOW GRANTS FOR 'phpergao'@'%';新建数据表
代码语言：javascript复制DROP TABLE IF EXISTS `workers_info`;
CREATE TABLE `workers_info` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`workername` varchar(20) NOT NULL,
`sex` enum('F','M','S') DEFAULT 'S',
`salary` int(11) DEFAULT '0',
`email` varchar(30) DEFAULT NULL,
`EmployedDates` date DEFAULT NULL,
`department` varchar(30) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;忘记了mysql密码
修改配置文件
代码语言：javascript复制[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
# ADD
skip-name-resolve
skip-grant-tables然后重启MySQL服务并免密码登录
代码语言：javascript复制service mysqld restart
mysql执行修改密码SQL
代码语言：javascript复制将root用户的密码统一设为'admin'
UPDATE mysql.user SET Password=password('123456') WHERE User='root';还原MySQL配置文件并重启服务
修改用户登录HOST
代码语言：javascript复制UPDATE mysql.user SET Host='&' WHERE User='root';参考：
http://renxiangzyq.iteye.com/blog/763837
