1、删除mysql的命令

sudo rm /usr/local/mysql

sudo rm -rf /usr/local/mysql*

sudo rm -rf /Library/StartupItems/MySQLCOM

sudo rm -rf /Library/PreferencePanes/My*

sudo rm -rf /Library/Receipts/mysql*

sudo rm -rf /Library/Receipts/MySQL*

sudo rm -rf /var/db/receipts/com.mysql.*

2、下载mysql

https://dev.mysql.com/downloads/mysql/5.7.html#downloads

选择下载

3、安装mysql

双击安装

选择继续

选择同意

选择安装

输入密码，选择安装

安装安装，弹出对话框，记住root密码，选择OK，安装成功，选择关闭

4、启动mysql

从launchpad中启动偏好设置

选择点击mysql

启动mysql

5、登入mysql

（1）从launchpad中启动终端

执行sudo su，输入密码

使用 vi .bash_profile 编辑环境环境变量

export MYSQL_HOME=/usr/local/mysql/

export PATH=$PATH:$MYSQL_HOME/bin

使用source .bash_profile命令立即生效环境变量

（2）使用命令登入密码不对：

sh-3.2# mysql -uroot -p

Enter password:

ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)

（3）设置不需要密码登入

sudo cp /usr/local/mysql/support-files/my-small.cnf /etc/my.cnf

发现并没有/usr/local/mysql/support-files/my-small.cnf这个文件。

我们自己使用vi /ect/my.cnf创建文件 下面是创建的文件内容。

#skip-grant-tables 将注释去掉。

[client]
port = 3306
default-character-set=utf8mb4
socket=/tmp/mysql.sock

[mysql]
port = 3306
default-character-set=utf8mb4
socket=/tmp/mysql.sock

[mysqld]
##########################
# summary
##########################
bind-address = 0.0.0.0
port = 3306
basedir=/usr/local/mysql
datadir=/data/mysql
socket=/tmp/mysql.sock
tmpdir = /tmp
pid-file=/tmp/mysqld.pid
#skip-grant-tables
#skip-networking

explicit_defaults_for_timestamp=1
lower_case_table_names=1

table_open_cache = 8000

##########################
# time out
##########################
connect_timeout = 20
wait_timeout = 86400

##########################
# connection
##########################
max_connections = 2000
max_user_connections = 1900
max_connect_errors = 100000
max_allowed_packet = 1G

##########################
# character set
##########################
character-set-server = utf8mb4
collation-server = utf8mb4_bin

##########################
# log bin
##########################
server-id = 1
log_bin = mysql-bin
# ROW、STATEMENT、MIXED
binlog_format = row
sync_binlog = 1
expire_logs_days = 7
binlog_cache_size = 128m
max_binlog_cache_size = 512m
max_binlog_size = 256M
master_info_repository=TABLE
relay_log_info_repository=TABLE
log_slave_updates=ON
binlog_checksum=none

binlog_ignore_db=mysql
binlog_ignore_db=information_schema
binlog_ignore_db=performation_schema
binlog_ignore_db=sys
##########################
# gtid
##########################
gtid_mode = on
enforce_gtid_consistency = on

##########################
# log relay
##########################
relay_log = mysql-relay-bin
relay_log_purge = on
relay_log_recovery = on
max_relay_log_size = 1G

##########################
# log error
##########################
log_error=/data/mysql/mysqld_error.log

##########################
# log slow
##########################
slow_query_log = on
slow_query_log_file = /data/mysql/mysqld_slow.log
long_query_time = 2
log_queries_not_using_indexes = on

##########################
# log general
##########################
general_log = on
general_log_file = /data/mysql/mysqld_gener.log


##########################
# thread pool
##########################
#thread_handling=pool-of-threads
#thread_handling=one-thread-per-connection
#thread_pool_oversubscribe=8 

##########################
# innodb
##########################
innodb_file_per_table=1
innodb_log_file_size=1024M
innodb_log_buffer_size=64M


##########################
# password policy
# after init 
##########################
#validate_password_length=4         
#validate_password_mixed_case_count=0
#validate_password_number_count=0
#validate_password_policy=0
#validate_password_special_char_count=0

重启mysql

通过终端登入mysql

（4）使用sql来修改mysql root密码

use mysql;

update user  set authentication_string =password("密码") where user='root';

flush privileges;

quit;

（5）使用 mysql -uroot -p

输入密码即可登入