数据库的基本操作【显哥出品，必为精品】

1.设置数据库密码

[root@db01 ~]# mysqladmin -uroot password '123'

2.使用密码登录数据库

#1.正确的登录方式
[root@db01 ~]# mysql -uroot -p123
[root@db01 ~]# mysql -u root -p123

#2.错误的登录方式
[root@db01 ~]# mysql -u root -p 123
Enter password: 
ERROR 1049 (42000): Unknown database '123'

如果使用-p或者--password参数，那么-p或--password和密码之间不能有空格

#3.规范的登录方式
[root@db01 ~]# mysql -u root -p
Enter password:

3.查看用户

mysql> select user,host from mysql.user;
+------+-----------+
| user | host      |
+------+-----------+
| root | 127.0.0.1 |
| root | ::1       |
|      | db01      |
| root | db01      |
|      | localhost |
| root | localhost |
+------+-----------+
6 rows in set (0.00 sec)

4.用户的安全优化

#删除没有用的用户
mysql> drop user 'root'@'::1';
Query OK, 0 rows affected (0.00 sec)

mysql> drop user ''@'db01';
Query OK, 0 rows affected (0.00 sec)

mysql> drop user ''@'localhost';
Query OK, 0 rows affected (0.00 sec)

mysql> select user,host from mysql.user;
+------+-----------+
| user | host      |
+------+-----------+
| root | 127.0.0.1 |
| root | db01      |
| root | localhost |
+------+-----------+
3 rows in set (0.00 sec)