1.登入資料庫，show databases命令檢視之前已經建立好的資料庫

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mairuan            |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
5 rows in set (0.01 sec)

2.使用drop database db_name刪除資料庫，如上mairuan是之前已經建立好的資料庫，現在刪除掉

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
4 rows in set (0.00 sec)

mysql> 

3.whereis 檢視mysql安裝路徑

[root@mair-001 ~]# whereis mysql;
 

mysql: /usr/bin/mysql /usr/lib64/mysql /usr/share/man/man1/mysql.1.gz
[root@mair-001 ~]# 

4.關閉mysql服務(service mysqld stop)

[root@mair-001 ~]# service mysqld stop;
Redirecting to /bin/systemctl stop mysqld.service
[root@mair-001 ~]# 

5.檢視還安裝過mysql相關的rpm包檔案（rpm -qa|grep mysql）

[[email protected]001 ~]# rpm -qa | grep mysql;
 

mysql80-community-release-el7-1.noarch
mysql-community-client-8.0.11-1.el7.x86_64
mysql-community-libs-8.0.11-1.el7.x86_64
mysql-community-server-8.0.11-1.el7.x86_64
mysql-community-common-8.0.11-1.el7.x86_64
mysql-community-libs-compat-8.0.11-1.el7.x86_64
[[email protected]001 ~]#

6.模糊匹配刪除掉mysql的安裝包的檔案（yum remove mysql）

[[email protected] ~]# yum remove mysql;
Loaded plugins: fastestmirror
Resolving Dependencies
--> Running transaction check
---> Package mysql-community-client.x86_64 0:8.0.11-1.el7 will be erased
--> Processing Dependency: mysql-community-client(x86-64) >= 8.0.0 for package: mysql-community-server-8.0.11-1.el7.x86_64
..........................

7.繼續刪除掉rpm包 （yum remove 通過第5步找到的rpm安裝包的檔案）

[root@mair-001 ~]# rpm -qa | grep mysql;
mysql80-community-release-el7-1.noarch
mysql-community-libs-8.0.11-1.el7.x86_64
mysql-community-common-8.0.11-1.el7.x86_64
mysql-community-libs-compat-8.0.11-1.el7.x86_64
[root@mair-001 ~]# yum remove mysql80-community-release-el7-1.noarch;
[root@mair-001 ~]# yum remove mysql-community-common-8.0.11-1.el7.x86_64;

8.檢查rpm包是否已經全部刪除，如下已經查詢不到rpm包

[root@mair-001 ~]# rpm -qa | grep mysql;
[root@mair-001 ~]# 

9.刪除mysql服務

[root@mair-001 ~]# chkconfig --list | grep -i mysql
[root@mair-001 ~]# chkconfig --del mysql

10.刪除分散mysql資料夾

[root@mair-001 ~]# whereis mysql
mysql: /usr/lib/mysql /usr/share/mysql

11.清空相關mysql的所有目錄以及檔案

[root@mair-001 ~]#rm -rf /usr/lib/mysql
[root@mair-001 ~]#rm -rf /usr/share/mysql
[root@mair-001 ~]#rm -rf /usr/my.cnf

至此，mysql就已經解除安裝完了