rpm  -qa | grep mariadb
rpm -e mariadb-libs-5.5.60-1.el7_5.x86_64  --nodeps

rpm -ivh mysql-community-common-5.7.10-1.el7.x86_64.rpm
rpm -ivh mysql-community-libs-5.7.10-1.el7.x86_64.rpm
rpm -ivh mysql-community-client-5.7.10-1.el7.x86_64.rpm
rpm -ivh mysql-community-server-5.7.10-1.el7.x86_64.rpm
rpm -ivh mysql-community-devel-5.7.10-1.el7.x86_64.rpm

service mysqld start
[root@l4cdb log]# cat /var/log/mysqld.log |grep -i password
2020-05-19T04:58:21.408080Z 1 [Note] A temporary password is generated for root@localhost: D34yB5*VD_fd

[root@ log]# mysql -u root -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.10

Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type ‘help;‘ or ‘\h‘ for help. Type ‘\c‘ to clear the current input statement.

mysql>

set password for ‘root‘@‘localhost‘=‘password‘

 grant all privileges on *.* to root@‘%‘ with grant option;

mysql> create database datacenter charset=utf8;
Query OK, 1 row affected (0.00 sec)

mysql> show database;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘database‘ at line 1
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| datacenter         |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
5 rows in set (0.00 sec)

[root@l4cdb mysql]# cat /etc/my.cnf|grep -v ^#|grep -v ^$
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
symbolic-links=0
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid