+------+----------------------+
| num | name |
+------+----------------------+
| 1 | Hello Everyone! | ← 确认被更新到新的值
+------+----------------------+
1 row in set (0.01 sec)
mysql> delete from test where num=1; ← 删除表内的值
Query OK, 1 row affected (0.00 sec)
mysql> select * from test; ← 确认删除结果
Empty set (0.01 sec)
mysql> drop table test; ← 删除表
Query OK, 0 rows affected (0.01 sec)
mysql> show tables; ← 查看表信息
Empty set (0.00 sec) ← 确认表已被删除
mysql> drop database test; ← 删除名为test的数据库
Query OK, 0 rows affected (0.01 sec)
mysql> show databases; ← 查看已存在的数据库
Empty set (0.01 sec) ← 确认test数据库已被删除（这里非root用户的关系，看不到名为mysql的数据库）
mysql> exit ← 退出MySQL服务器
Bye
然后，删除测试用过的遗留用户。
[root@sample ~]# mysql -u root -p ← 通过密码用root登录
Enter password: ← 在这里输入密码
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 12 to server version: 4.1.20
Type 'help;' or '\h' for help. Type '\c' to clear the buffer.
mysql> revoke all privileges on *.* from centospub@localhost; ← 取消centospub用户对数据库的操作权限
Query OK, 0 rows affected (0.00 sec)
mysql> delete from mysql.user where user='centospub' and host='localhost'; ← 删除centospub用户
Query OK, 1 row affected (0.01 sec)
mysql> select user from mysql.user where user='centospub'; ← 查找用户centospub，确认已删除与否
Empty set (0.01 sec) ← 确认centospub用户已不存在
mysql> flush privileges; ← 刷新，使以上操作生效
Query OK, 0 rows affected (0.01 sec)
mysql> exit
Bye
5、最后，重新启动一次HTTP服务，让php-mysql反映到HTTP服务中。
[root@sample ~]# /etc/rc.d/init.d/httpd restart ← 重新启动HTTP服务
Stopping httpd: [ OK ]
Starting httpd: [ OK ]