创建用户账号
MariaDB [mydb]> create user yonghuming@'172.16.%.%' identified by 'yonghumima';
Query OK, 0 rows affected (0.00 sec)
MariaDB [mydb]>
忘记用户密码后修改密码
>>方法一：
MariaDB [mydb]> set password for 'yonghuming'@'172.16.%.%' = password('mageedu');
Query OK, 0 rows affected (0.00 sec)
MariaDB [mydb]> flush privileges; <-- 让MySQL重新加载授权表,即修改密码后让其即时生效
Query OK, 0 rows affected (0.00 sec)
>>方法二：
MariaDB [mydb]> select user,host,password from mysql.user;
+------------+---------------+-------------------------------------------+
| user | host | password |
+------------+---------------+-------------------------------------------+
| root | localhost | |
| root | host1.centos7 | |
| root | 127.0.0.1 | |
| root | ::1 | |
| | localhost | |
| | host1.centos7 | |
| test | 192.168.10.% | *9A94EE7D14C10908118B62D2DA88E6932E11E438 | <-- 修改前结尾是E438
| wxg | 192.168.%.% | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |
| yonghuming | 172.16.%.% | *9A94EE7D14C10908118B62D2DA88E6932E11E438 | <-- 相同密码的加密后生成的也相同
+------------+---------------+-------------------------------------------+
9 rows in set (0.00 sec)
MariaDB [mydb]> update mysql.user set password=password('123456') where user='test' and host='192.168.10.%';
(上面的整条命令的意思是：把test用户的密码修改为‘123456’ where 是条件，后面一定要跟条件)
Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0
MariaDB [mydb]> select user,host,password from mysql.user;
+------------+---------------+-------------------------------------------+
| user | host | password |
+------------+---------------+-------------------------------------------+
| root | localhost | |
| root | host1.centos7 | |
| root | 127.0.0.1 | |
| root | ::1 | |
| | localhost | |
| | host1.centos7 | |
| test | 192.168.10.% | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | <--修改后是2AD9
| wxg | 192.168.%.% | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | <--相同密码生成的password字段的加密码相同
| yonghuming | 172.16.%.% | *9A94EE7D14C10908118B62D2DA88E6932E11E438 |
+------------+---------------+-------------------------------------------+
9 rows in set (0.00 sec)
（注意当我们调用内键变量password修改密码的时候，它是对称的，同样的密码所生成的加密码是相同的！细看表中test和wxg的加密码）
MariaDB [mydb]> flush privileges; <-- 让MySQL重新加载授权表,即修改密码后让其即时生效
Query OK, 0 rows affected (0.00 sec)
MariaDB [mydb]>
查看当前数据库
[root@centos7 ~]#mysql -uroot -p
Enter password:
Welcome to the MariaDB monitor. Commands end with ; or \g.
MariaDB [(none)]> show databases; <---查看当前数据库
+--------------------+
| Database |
+--------------------+
| information_schema |
| bjtechan |
| mysql |
| performance_schema |
+--------------------+
4 rows in set (0.09 sec)
MariaDB [(none)]>
切换到某个数据库去访问
MariaDB [bjtechan]> use mysql; <---切换到mysql数据库
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
MariaDB [mysql]>
查看当前数据库有哪些表
MariaDB [mysql]> show tables; <---查看当前数据库有哪些表
+---------------------------+
| Tables_in_mysql |
+---------------------------+
| columns_priv |
| db |
| event |
| func |
| general_log |
| help_category |
| help_keyword |
| help_relation |
| help_topic |
| host |
| ndb_binlog_index |
| plugin |
| proc |
| procs_priv |
| proxies_priv |
| servers |
| slow_log |
| tables_priv |
| time_zone |
| time_zone_leap_second |
| time_zone_name |
| time_zone_transition |
| time_zone_transition_type |
| user |
+---------------------------+
24 rows in set (0.00 sec)
MariaDB [mysql]>
查看某一个表的表结构
MariaDB [mysql]> desc user; <---查看表结构：desc 加 表名
+------------------------+-----------------------------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+------------------------+-----------------------------------+------+-----+---------+-------+
| Host | char(60) | NO | PRI | | |
| User | char(16) | NO | PRI | | |
| Password | char(41) | NO | | | |
| Select_priv | enum('N','Y') | NO | | N | |
| Show_db_priv | enum('N','Y') | NO | | N | |
| Super_priv | enum('N','Y') | NO | | N | |
| Repl_slave_priv | enum('N','Y') | NO | | N | |
| ssl_type | enum('','ANY','X509','SPECIFIED') | NO | | | |
| ssl_cipher | blob | NO | | NULL | |
| x509_issuer | blob | NO | | NULL | |
| x509_subject | blob | NO | | NULL | |
| max_questions | int(11) unsigned | NO | | 0 | |
| max_updates | int(11) unsigned | NO | | 0 | |
| max_connections | int(11) unsigned | NO | | 0 | |
| max_user_connections | int(11) | NO | | 0 | |
| plugin | char(64) | NO | | | |
| authentication_string | text | NO | | NULL | |
+------------------------+-----------------------------------+------+-----+---------+-------+
42 rows in set (0.00 sec)
MariaDB [mysql]>
选择性查看一个表格的某些字段
MariaDB [mysql]> select host,user,password from user; <---查看user表格的主机用户密码信息
+---------------+------+-------------------------------------------+
| host | user | password |
+---------------+------+-------------------------------------------+
| localhost | root | *9A94EE7D14C10908118B62D2DA88E6932E11E438 |
| centos7.3.wxg | root | *9A94EE7D14C10908118B62D2DA88E6932E11E438 |
| 127.0.0.1 | root | *9A94EE7D14C10908118B62D2DA88E6932E11E438 |
| ::1 | root | *9A94EE7D14C10908118B62D2DA88E6932E11E438 |
+---------------+------+-------------------------------------------+
4 rows in set (0.01 sec)
MariaDB [mysql]>
显示当前的用户名
MariaDB [mysql]> select user(); <---显示当前的用户名
+----------------+
| user() |
+----------------+
| root@localhost | <---当前登录的用户，这才是完整的用户名；用户@主机名（可以是ip地址）
+----------------+
1 row in set (0.00 sec)
MariaDB [mysql]>
创建数据库
MariaDB [(none)]> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| bjtechan |
| mysql |
| performance_schema |
+--------------------+
4 rows in set (0.00 sec)
MariaDB [(none)]> create database testdb; <---创建一个叫testdb的数据库
Query OK, 1 row affected (0.00 sec)
MariaDB [(none)]> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| bjtechan |
| mysql |
| performance_schema |
| testdb |
+--------------------+
5 rows in set (0.00 sec)
MariaDB [(none)]> quit <---退出数据库
Bye
[root@centos7 ~]#
显示当前登录用户
MariaDB [mydb]> select current_user(); <-- 内键函数，显示当前登录用户
+----------------+
| current_user() |
+----------------+
| root@localhost |
+----------------+
1 row in set (0.00 sec)
MariaDB [mydb]>
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