1、 导入hellodb.sql生成数据库

登录mysql数据库，导入SQL脚本并执行

[root@localhost][(none)]> \! ls /data
hellodb_innodb.sql
[root@localhost][(none)]> source /data/hellodb_innodb.sql
[root@localhost][hellodb]> SHOW TABLES;
+-------------------+
| Tables_in_hellodb |
+-------------------+
| classes           |
| coc               |
| courses           |
| scores            |
| students          |
| teachers          |
| toc               |
+-------------------+
7 rows in set (0.00 sec)

[root@localhost][hellodb]>

1-1 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

[root@localhost][hellodb]> SELECT Name,Age FROM students WHERE Gender='M' and Age>25;
+--------------+-----+
| 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 (0.00 sec)

[root@localhost][hellodb]>

1-2 以ClassID为分组依据，显示每组的平均年龄

[root@localhost][hellodb]> SELECT ROUND(AVG(Age), 0) as Avg_Age,ClassID FROM students GROUP BY ClassID;
+---------+---------+
| Avg_Age | ClassID |
+---------+---------+
|      36 |       2 |
|      21 |       1 |
|      25 |       4 |
|      20 |       3 |
|      46 |       5 |
|      20 |       7 |
|      21 |       6 |
|      64 |    NULL |
+---------+---------+
8 rows in set (0.00 sec)

[root@localhost][hellodb]>

1-3 显示第2题中平均年龄大于30的分组及平均年龄

root@localhost][hellodb]> SELECT ROUND(AVG(Age), 0) as Avg_Age,ClassID FROM students GROUP BY ClassID HAVING Avg_age>30;
+---------+---------+
| Avg_Age | ClassID |
+---------+---------+
|      36 |       2 |
|      46 |       5 |
|      64 |    NULL |
+---------+---------+
3 rows in set (0.00 sec)

[root@localhost][hellodb]>

1-4 显示以L开头的名字的同学的信息

[root@localhost][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 (0.00 sec)

[root@localhost][hellodb]>

2、数据库授权magedu用户，允许192.168.1.0/24网段可以连接mysql

CREATE USER magedu@'192.168.1.%' IDENTIFIED BY '123456';
FLUSH PRIVILEGES;