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
