一、下载dmg包安装

　　1、下载MySQL dmg 包, 从官网 : http://www.mysql.com/downloads/ 进入, 点击下方的DOWNLOADS : MySQL Community Server

　　选择dmg文件下载

　　接着, 会跳转到如下页面, 你只需要选择不登录,直接下载即可　　

　　2、进入系统偏好设置,点击MySQL,开启MySQL服务

　　3、环境变量配置（windows也是这样run的。可以不配置, 但每次必须在msyql的安装目录下,执行mysql命令。）

　　进入到用户目录下 执行 vim .bash_profile   。添加如下内容

##mysql

export PATH=${PATH}:/usr/local/mysql/bin

　　快速启动、结束MySQL服务, 可以使用alias命令

alias mysqlstart='sudo /usr/local/mysql/support-files/mysql.server start'

alias mysqlstop='sudo /usr/local/mysql/support-files/mysql.server stop'

　　我们就可以在任何地方执行mysql命令了。

　　如果你还没有配置环境变量, 可以先进入MySQL安装目录, 再执行MySQL相关命令。安装目录在/user/local/mysql版本 。 我的目录是

/usr/local/mysql-5.7.16-osx10.11-x86_64

mysql>update mysql.user set authentication_string=password('123456') where user='root' ;

mysql> FLUSH PRIVILEGES;

mysql> quit

 5.mysqlstop   然后 mysqlstart   （因为我输入sudo mysql restart 还是报错ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)

 6. mysql -uroot -p

 7. 输入重置后的密码

 8  进入mysql交互模式 输入“ show databases;"  报错“ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement.“

[mysql> set password=password("root");

[mysql> flush privileges;

[mysql> help contents

You asked for help about help category: "Contents"

For more information, type 'help <item>', where <item> is one of the following

categories:

Account Management

Administration

Compound Statements

Data Definition

Data Manipulation

Data Types

Functions

Functions and Modifiers for Use with GROUP BY

Geographic Features

Help Metadata

Language Structure

Plugins

Procedures

Storage Engines

Table Maintenance

Transactions

User-Defined Functions

Utility

[mysql> show databases;

+--------------------+

| Database           |

+--------------------+

| information_schema |

| guest_test         |

| mysql              |

| performance_schema |

| sys                |

问题解决