Basic usage of MySQL in centos8

1、 Import hellodb.sql Generate database

Ready to install mariadb-server

yum -y install  mariadb-server
systemctl enable  --now mariadb.service 

 

 

  Import database and table files

(1) stay students In the table , Query age is greater than 25 year , And the name and age of the male students

MariaDB [hellodb]> select name students_name,age students_age from students where age>=25 and gender='M';

(2) With ClassID To group by , Show the average age of each group

MariaDB [hellodb]> select classid ,avg(age) from students group by classid;

(3) According to the first 2 The average age in the questions is greater than 30 And the average age

MariaDB [hellodb]> select classid ,avg(age)   Average age  from students group by classid having  Average age >30;

(4) Display with L Information about the students with the first name

MariaDB [hellodb]> select * from students where name like 'L%';

2、 Database authorization magedu user , allow 192.168.1.0/24 Segments can be connected mysql

Preparation :

echo 1 > /proc/sys/net/ipv4/ip_forward-------- Turn on the routing function 

MariaDB [(none)]> grant all privileges on *.* to 'magedu'@'192.168.1.%' identified by '123456';----------------- Create users and authorize them, but in mysql-8.0 This function has been canceled 

 

[[email protected] ~]# mysql -umagedu -h10.0.0.6 -p123456