Normally, you can do everything with MySQL Workbench or software like that, but sometimes, you need to know how to use basic MySQL commands to complete your tasks.
How to install MySQL on Ubuntu, Debian and CentOS
If you don’t have MySQL server installed on your server, you can quickly download it. Getting the right packets depends on your system, but it’s very easy if you’re using Debian / Ubuntu based systems or CentOS. Use a complex password for the root account when the system asks you to type it. Do not use same password what you use for your server’s root / superuser account.
Debian and Ubuntu:
sudo apt-get install mysql-server
sudo yum install mysql-server /etc/init.d/mysqld start
Now you should have the MySQL server up and running.
You can start, restart and stop the server easily:
sudo /etc/init.d/mysql restart | stop | start
How to access the MySQL server
I prefer a graphical interface for creating and managing databases and users (ex. MySQL Workbench, HeidiSQL, phpMyAdmin), but you can also connect to the MySQL server by typing the following command into terminal:
mysql -u username -p
If you’re logging in the first time, then you probably don’t have any other users than root and the password for that user is whatever you put when you installed the MySQL server.
Remember, all MySQL commands end with a semicolon (;). The command will not execute without it.
It is common practise that MySQL commands are written in uppercase and everything else, like database and user names, are in lowercase to make them easier to distinguish. However, the MySQL command line is not case sensitive and you can write everything in lowercase if you like to.
How to create, access and delete a MySQL Database
Let’s make a database called test. Log in to the MySQL server as root and type:
CREATE DATABASE test; CREATE DATABASE test CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
If you want to know what databases are available:
The command above show all the databases that are created in the MySQL server.
After creating a database, you can start using it and store information in it. Open the database by typing:
Now you’re in the database and can create tables. Remember, table and database names are case sensitive.
How to create a table inside of the database
Let’s create a table called test. There have to be a PRIMARY KEY in every table and in this case the key is AUTO_INCREMENT meaning it automatically numbers each row. The key must be unique, because rows are identified by it.
There will be also name and birthday. Name is using VARCHAR and bday is DATE. MySQL requires that dates be written as yyyy-mm-dd.
CREATE TABLE test ( id INT NOT NULL PRIMARY KEY AUTO_INCREMENT, name VARCHAR(20), bday DATE );
Now you can see what you just did by typing:
How to add information to a MySQL table
Use this format to insert information into each row:
INSERT INTO 'test' ('id','name','food','confirmed','signup_date') VALUES (NULL, "Max", '1977-07-17');
If you want to see what table has been eating:
SELECT * FROM test;
You can also update exiting data:
UPDATE 'test' SET 'bday' = '1981-07-17' WHERE 'test'.'name' ='Max';
How to delete a database
When database is no longer needed you can drop it.
DROP DATABASE test;
How to create a new MySQL user
CREATE USER 'newuser'@'localhost' IDENTIFIED BY 'password';
There should be only one database per user. It is more secure.
MySQL user permission
The next command will give all the rights to the certain database but the user can not grant privileges to other users or take anything from them. The user can control the database, create tables and data, and drop everything. That is the most common way to give access to the database.
GRANT ALL PRIVILEGES ON test.* TO 'newuser'@'localhost';
If you really want to, you can also give the user superuser rights with grant option. That is not recommended when working with CMS or apps.
GRANT ALL PRIVILEGES ON mydb.* TO 'myuser'@'%' WITH GRANT OPTION;
You can also give certain permissions to the database or the table if you don’t want to give all the rights.
GRANT [type of permission] ON [database name].[table name] TO 'username'@'localhost';
Or you can revoke some rights if the user don’t need them:
REVOKE [type of permission] ON [database name].[table name] FROM 'username'@'localhost';
After making a change, you should flush privileges.
Delete a MySQL user
DROP USER 'demo'@'localhost';
mysqlcheck -u username -p --optimize --all-databases
Thanks for reading!