1棒掠、 導(dǎo)入hellodb.sql生成數(shù)據(jù)庫
(1) 在students表中，查詢年齡大于25歲整葡，且為男性的同學的名字和年齡
(2) 以ClassID為分組依據(jù)，顯示每組的平均年齡
(3) 顯示第2題中平均年齡大于30的分組及平均年齡
(4) 顯示以L開頭的名字的同學的信息
#導(dǎo)入hellodb.sql
[root@centos8 ~]# mysql -uroot -pyyang <hellodb.sql
mysql: [Warning] Using a password on the command line interface can be insecure.
#檢查導(dǎo)入數(shù)據(jù)庫
[root@centos8 ~]# mysql -uroot -pyyang
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 5
Server version: 5.7.31-log MySQL Community Server (GPL)
Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| hellodb |
| mysql |
| performance_schema |
| sys |
+--------------------+
5 rows in set (0.00 sec)
mysql> use hellodb;
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
mysql> show tables;
+-------------------+
| Tables_in_hellodb |
+-------------------+
| classes |
| coc |
| courses |
| scores |
| students |
| teachers |
| toc |
+-------------------+
7 rows in set (0.01 sec)
# 在students表中鲫懒，查詢年齡大于25歲，且為男性的同學的名字和年齡
mysql> 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 (0.01 sec)
#以ClassID為分組依據(jù)刽辙，顯示每組的平均年齡
mysql> select classid,avg(age) as 平均年齡 from students group by classid;
+---------+--------------+
| classid | 平均年齡 |
+---------+--------------+
| NULL | 63.5000 |
| 1 | 20.5000 |
| 2 | 36.0000 |
| 3 | 20.2500 |
| 4 | 24.7500 |
| 5 | 46.0000 |
| 6 | 20.7500 |
| 7 | 19.6667 |
+---------+--------------+
8 rows in set (0.00 sec)
#顯示第2題中平均年齡大于30的分組及平均年齡
mysql> select classid,avg(age) as 平均年齡 from students group by classid having 平均年齡 > 30;
+---------+--------------+
| classid | 平均年齡 |
+---------+--------------+
| NULL | 63.5000 |
| 2 | 36.0000 |
| 5 | 46.0000 |
+---------+--------------+
3 rows in set (0.03 sec)
#顯示以L開頭的名字的同學的信息
mysql> 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)
2窥岩、數(shù)據(jù)庫授權(quán)magedu用戶，允許192.168.1.0/24網(wǎng)段可以連接mysql
[root@centos8 ~]# mysql -uroot -pyyang
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 5
Server version: 5.7.31-log MySQL Community Server (GPL)
Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> grant all on *.* to 'magedu'@'192.168.1.%' IDENTIFIED BY '12345678';
Query OK, 0 rows affected (0.05 sec)
mysql> select user,host from user;
+---------------+-------------+
| user | host |
+---------------+-------------+
| magedu | 192.168.1.% |
| mysql.session | localhost |
| mysql.sys | localhost |
| root | localhost |
+---------------+-------------+
4 rows in set (0.00 sec)
