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MySQL Tutorial (part 1)Some commands in MySQL you need to be remembered:

1. Show version:

mysql> select version();

+-----------+

| version() |

+-----------+

| 5.5.12 |

+-----------+

1 row in set (0.03 sec)

mysql>

2. Create a new database:

mysql> create database demo;

Query OK, 1 row affected (0.01 sec)

mysql> show databases;

+--------------------+

| Database |

+--------------------+

| information_schema |

| demo |

| mysql |

| performance_schema |

| test |

| testdb |

+--------------------+

6 rows in set (0.00 sec)

mysql>

3. Create a new table:

mysql> create table audience (Id int primary key auto_increment, Name varchar(100)) engine = InnoDB;

Query OK, 0 rows affected (0.16 sec)

mysql> show tables;

+------------------+


mysql>

6. Describe the structure of a table:

mysql> describe audience;

+-------+--------------+------+-----+---------+----------------+

| Field | Type | Null | Key | Default | Extra |

+-------+--------------+------+-----+---------+----------------+

| Id | int(11) | NO | PRI | NULL | auto_increment |

| Name | varchar(100) | YES | | NULL | |

+-------+--------------+------+-----+---------+----------------+


mysql>

Other way:

mysql> show create table audience;

+----------+--------------------------------------------------------------------------------------------------+

| Table | Create Table |

+----------+--------------------------------------------------------------------------------------------------+

| audience | CREATE TABLE àudience` (Ìd` int(11) NOT NULL AUTO_INCREMENT,`Name` varchar(100) DEFAULT NULL, PRIMARY KEY (Ìd`)) ENGINE=InnoDB DEFAULT CHARSET=latin1 |

+----------+--------------------------------------------------------------------------------------------------+


mysql>

7. Use a database:

We have to use this command before you want to interact with a database and its tables.

mysql> use testdb;

Database changed

mysql>

8. Create a new user:

mysql> create user 'ledlong'@'localhost' identified by '123456';


mysql> use mysql;

Database changed

mysql> select Host, User, Password from user;

+-----------+---------+-------------------------------------------+

| Host | User | Password |

+-----------+---------+-------------------------------------------+

| localhost | root | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| localhost | admin | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| localhost | ledlong | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

+-----------+---------+-------------------------------------------+


mysql>

9. Grant privilege for a user:

mysql> grant all privileges on testdb.* to 'ledlong'@'localhost';


This way can be used when you have already created a new user before.

Other way:

mysql> grant all privileges on testdb.* to 'ledlong'@'localhost' identified by '123456';


This way can be used when you have not created a new user before.

Use “flush privileges” command to active all privileges above:

mysql> flush privileges;


10. Drop a database:


+--------------------+

| Database |

+--------------------+


| demo |

| mysql |


| test |

| testdb |

+--------------------+

+----+-------------------+

| 1 | Jack London |



| 4 | Emile Zola |



| 11 | Le Vinh Hien |

+----+-------------------+


mysql>

14. UPDATE command:

UPDATE <Table_Name> SET (Column_Name = ‘value’) WHERE (Condition);


+----+-------------------+

| Id | Name |

+----+-------------------+

| 1 | Jack London |



| 4 | Emile Zola |




+----+-------------------+


mysql> update authors set Name = 'Le Van Hue' where Id = 11;


Rows matched: 1 Changed: 1 Warnings: 0


+----+-------------------+

| Id | Name |

+----+-------------------+

| 1 | Jack London |



| 4 | Emile Zola |



| 11 | Le Van Hue |

+----+-------------------+


mysql>

15. DELETE command:

DELETE FROM <Table_Name> WHERE (Condition);


+----+-------------------+

| Id | Name |

+----+-------------------+

| 1 | Jack London |



| 4 | Emile Zola |



| 11 | Le Van Hue |

+----+-------------------+


mysql> delete from authors where Id = 11;



+----+-------------------+

| Id | Name |

+----+-------------------+

| 1 | Jack London |



| 4 | Emile Zola |



+----+-------------------+


mysql>

16. WHERE command:

… WHERE (Condition);

This command often accompanies some commands like SELECT, UPDATE, DELETE if you want to receive a result that depends on a condition.

a. With SELECT command:


+----+-------------------+

| Id | Name |

+----+-------------------+

| 1 | Jack London |



| 4 | Emile Zola |



+----+-------------------+


mysql> select * from books;

+----+----------+----------------------+

| Id | AuthorId | Title |

+----+----------+----------------------+

| 1 | 1 | Call of the Wild |

| 2 | 1 | Martin Eden |

| 3 | 2 | Old Goriot |

| 4 | 2 | Cousin Bette |

| 5 | 3 | Jew Suess |

+-------------------+----------------------+










+-------------------+----------------------+


a. In decrement order:

ORDER BY <Column_name> DESC

mysql> select authors.Name, books.Title from (authors, books) where (authors.Id=books.AuthorId) order by authors.Name DESC;

+-------------------+----------------------+

| Name | Title |

+-------------------+----------------------+










+-------------------+----------------------+


mysql>

b. In increment order:

ORDER BY <Column_Name> ASC;

mysql> select authors.Name, books.Title from (authors, books) where (authors.Id=books.AuthorId) order by authors.Name ASC;

+-------------------+----------------------+

| Name | Title |

+-------------------+----------------------+










+-------------------+----------------------+


mysql>

18. GROUP BY command:

GROUP BY clause is used to combine database records with identical values into a single record.


+----+-------------------+

| Id | Name |

+----+-------------------+

| 1 | Jack London |



| 4 | Emile Zola |



| 12 | Jack London |

| 13 | Emile Zola |



+----+-------------------+


mysql> select * from authors group by Name;

+----+-------------------+

| Id | Name |

+----+-------------------+

| 4 | Emile Zola |


| 1 | Jack London |





+----+-------------------+


mysql>

Another example:

mysql> select * from sales;

+----+-------------------+------+

| Id | Name | sell |

+----+-------------------+------+

| 1 | Le Duong Long | 12 |

| 2 | Tran Thu Ha | 2 |

| 3 | Le Vinh Hien | 20 |

| 4 | Duong Thi Hop | 30 |

| 5 | Hoang Minh Phuong | 3 |

| 6 | Le Van Hue | 23 |

| 7 | Tran Thu Ha | 24 |



| 10 | Le Duong Long | 112 |

| 11 | Le Vinh Hien | 200 |

+----+-------------------+------+


mysql> select Name, sum(sell) from sales group by Name;

+-------------------+-----------+

| Name | sum(sell) |

+-------------------+-----------+

| Duong Thi Hop | 73 |

| Hoang Minh Phuong | 42 |

| Le Duong Long | 124 |

| Le Van Hue | 23 |

| Le Vinh Hien | 220 |

| Tran Thu Ha | 26 |

+-------------------+-----------+


mysql>

19. LIMIT command:

If you want to limit the number of rows which is displayed in output results:


+----+-------------------+

| Id | Name |

+----+-------------------+

| 1 | Jack London |



| 4 | Emile Zola |



+----+-------------------+


mysql> select * from authors limit 4;

+----+-------------------+

| Id | Name |

+----+-------------------+

| 1 | Jack London |



| 4 | Emile Zola |

+----+-------------------+


mysql>

Sometime GROUP BY and HAVING go together as follow:

mysql> select Name, sum(sell) from sales group by Name;

+-------------------+-----------+


+-------------------+-----------+




| Le Van Hue | 23 |



+-------------------+-----------+


mysql> select Name, sum(sell) from sales group by Name having sum(sell) > 100;

+---------------+-----------+


+---------------+-----------+



+---------------+-----------+


mysql>

20. LIKE command:


+----+-------------------+------+


+----+-------------------+------+


| 2 | Tran Thu Ha | 2 |




| 6 | Le Van Hue | 23 |

| 7 | Tran Thu Ha | 24 |



| 10 | Le Duong Long | 112 |

| 11 | Le Vinh Hien | 200 |

+----+-------------------+------+


I just want to list out who has name with letter L at the beginning:

mysql> select * from sales where Name like 'L%';

+----+---------------+------+


+----+---------------+------+



| 6 | Le Van Hue | 23 |

| 10 | Le Duong Long | 112 |

| 11 | Le Vinh Hien | 200 |

+----+---------------+------+


Other examples:

mysql> select distinct Name from sales where Name like 'H%';

+-------------------+

| Name |

+-------------------+

| Hoang Minh Phuong |

+-------------------+


mysql> select distinct Name from sales where Name like '%H%';

+-------------------+

| Name |

+-------------------+

| Tran Thu Ha |

| Le Vinh Hien |

| Duong Thi Hop |

| Hoang Minh Phuong |

| Le Van Hue |

+-------------------+


mysql>

21. AS command:

Display output results are in an another name


+----+-------------------+------+


+----+-------------------+------+


| 2 | Tran Thu Ha | 2 |




| 6 | Le Van Hue | 23 |

| 7 | Tran Thu Ha | 24 |



| 10 | Le Duong Long | 112 |

| 11 | Le Vinh Hien | 200 |

+----+-------------------+------+


mysql> select Name, sum(sell) as sumary from sales group by Name;

+-------------------+--------+

| Name | sumary |

+-------------------+--------+




| Le Van Hue | 23 |



+-------------------+--------+


mysql>

22. Change password for an existing user:

a. The first way:

Mysql> use mysql;

Database changed


+-----------+---------+-------------------------------------------+


+-----------+---------+-------------------------------------------+


| localhost | admin | *3620754A963ECB3D7296097F9DA00C1FA5476B03 |


+-----------+---------+-------------------------------------------+


mysql> set password for 'admin'@'localhost' = password('123456');



+-----------+---------+-------------------------------------------+


+-----------+---------+-------------------------------------------+




+-----------+---------+-------------------------------------------+


mysql>

b. The second way:

mysql> grant all privileges on testdb.* to 'admin'@'localhost' identified by '123abc';





+-----------+---------+-------------------------------------------+


+-----------+---------+-------------------------------------------+




+-----------+---------+-------------------------------------------+


mysql>

c. The third way:


+-----------+---------+-------------------------------------------+


+-----------+---------+-------------------------------------------+




+-----------+---------+-------------------------------------------+


mysql> update mysql.user set Password = password('123456') where user = 'admin' and host = 'localhost';


Rows matched: 1 Changed: 1 Warnings: 0




+-----------+---------+-------------------------------------------+


+-----------+---------+-------------------------------------------+




+-----------+---------+-------------------------------------------+


mysql>

23. Quit MySQL:

mysql> quit;

24. Backup database:

You can use mysqldump tool to backup database:

If you install mysql server on a Windows machine, you can find out mysqldump tool in C:\Program Files\MySQL\MySQL Server 5.5\bin>

You can backup databases as follow:

C:\Program Files\MySQL\MySQL Server 5.5\bin>mysqldump -u root -p testdb > C:\testdb.sql

Enter password: ******

The above clause will generate testdb.sql file into C partition. This file will contain all of commands which are used to backup for testdb database.

You can backup multiple databases in mysql through following clause:

C:\Program Files\MySQL\MySQL Server 5.5\bin>mysqldump -u root -p --databases testdb mysql > C:\testdb.sql


You also can backup all of databases in mysql through following clause:

C:\Program Files\MySQL\MySQL Server 5.5\bin>mysqldump -u root -p --all-databases > C:\testdb.sql


Note that: In Windowns operating system, mysql and musqldump are seperated programs, so you cannot backup database directly in mysql program if using mysqldump. In Linux environment, you can perform directly mysqldump command in mysql

25. Backup table:

If you just want to backup a table or some tables in a database in mysql, you can do as follow:

C:\Program Files\MySQL\MySQL Server 5.5\bin>mysqldump.exe -u root -p testdb sales > sales.sql


The above clause can help you to backup the table sales from the database testdb and generate to sales.sql file. This file is placed in the same folder with mysqldump tool. Certainly, you can identify where is sales.sql placed.

26. Restore a database:

C:\Program Files\MySQL\MySQL Server 5.5\bin>mysql -u root -p testdb < C:\testdb.sql


Reference:

[1] http://zetcode.com/databases/mysqltutorial/

Hanoi, April 21th, 2013

ledlong

http://zetcode.com/databases/mysqltutorial/

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