1、 导入hellodb.sql生成数据库
MariaDB [(none)]> source /scripts/hellodb_innodb.sql
(1) 在students表中，查询年龄大于25岁，且为男性的同学的名字和年龄
MariaDB [hellodb]> select Name,Age from students where age > 25 and gender = 'M';
+--------------+-----+
| Name | Age |
+--------------+-----+
| Xie Yanke | 53 |
| Ding Dian | 32 |
| Yu Yutong | 26 |
| Shi Qing | 46 |
| Tian Boguang | 33 |
| Xu Xian | 27 |
| Sun Dasheng | 100 |
+--------------+-----+
7 rows in set (0.001 sec)
(2) 以ClassID为分组依据，显示每组的平均年龄
MariaDB [hellodb]> select Classid,avg(age) from students where classid is not null group by classid;
+---------+----------+
| Classid | avg(age) |
+---------+----------+
| 1 | 20.5000 |
| 2 | 36.0000 |
| 3 | 20.2500 |
| 4 | 24.7500 |
| 5 | 46.0000 |
| 6 | 20.7500 |
| 7 | 19.6667 |
+---------+----------+
7 rows in set (0.001 sec)
(3) 显示第2题中平均年龄大于30的分组及平均年龄
MariaDB [hellodb]> select Classid,avg(age) from students where classid is not null group by classid having avg(age) > 30;
+---------+----------+
| Classid | avg(age) |
+---------+----------+
| 2 | 36.0000 |
| 5 | 46.0000 |
+---------+----------+
2 rows in set (0.001 sec)
(4) 显示以L开头的名字的同学的信息
MariaDB [hellodb]> select * from students where name like 'L%';
+-------+-------------+-----+--------+---------+-----------+
| StuID | Name | Age | Gender | ClassID | TeacherID |
+-------+-------------+-----+--------+---------+-----------+
| 8 | Lin Daiyu | 17 | F | 7 | NULL |
| 14 | Lu Wushuang | 17 | F | 3 | NULL |
| 17 | Lin Chong | 25 | M | 4 | NULL |
+-------+-------------+-----+--------+---------+-----------+
3 rows in set (0.001 sec)
2、数据库授权magedu用户，允许192.168.1.0/24网段可以连接mysql
MariaDB [mysql]> create user 'magedu'@'192.168.1.%' identified by 'magedu';
Query OK, 0 rows affected (0.001 sec)
MariaDB [mysql]> show grants for 'magedu'@'192.168.1.%';
+-----------------------------------------------------------------------------------------------------------------+
| Grants for magedu@192.168.1.% |
+-----------------------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO `magedu`@`192.168.1.%` IDENTIFIED BY PASSWORD '*6B8CCC83799A26CD19D7AD9AEEADBCD30D8A8664' |
+-----------------------------------------------------------------------------------------------------------------+
1 row in set (0.000 sec)
