查看mysql用户信息
select host,user,plugin from mysql.user;
mysql 8.0默认是使用caching_sha2_password，修改为native方式，并且设置密码。
ALTER USER 'root'@'%' IDENTIFIED WITH mysql_native_password BY '123456';
flush privileges;
新建用户
USE mysql;
CREATE USER 'user'@'%' IDENTIFIED BY '123456';
GRANT ALL ON *.* TO 'user'@'%';
FLUSH PRIVILEGES;