mysql forgot password or MySQL Server has been unable to connect, uninstall and install

Why uninstall, 1. Forgot root password, 2. MySQL Server has been unable to connect. terminal execution.

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.*

mysql install

Download from the official website . Community -> MySQL Community Server. Pull down and select the system to download directly.

The .dmg file is installed foolishly, and a pop-up box for the root password will pop up at the end. Be sure to copy the password, copy the password, and copy the password. Otherwise, uninstall-install again.

A temporary password is generated for root@localhost: 8pK.fSfp#QhK

After the installation is complete: Preferences->Bottom->mysql->start the server.

Terminal: , Enter the mysqlroot user and enter the password below. , Enter the password, after reinstallation, the initial password is the password to be copied and saved above. mysql -u root -p  Enter password:

After entering mysql, you can change the password to the password you remember.

mysql> set password = password('新密码')

Create a new user and set a password create user 'lfpython'@'localhost' identified by 'lfpython'

Create a data table create database testDB;

Authorize the user to have all permissions on the database: grant all privileges on pytest.* to lfpython@localhost identified by 'lfpython'