Here are examples of how to solve some common problems with MySQL.

Some of the examples use the tableshop to hold the price of each article (item number) for certain traders (dealers). Supposing that each trader has a single fixed price per article, then (article,dealer) is a primary key for the records.

Start the command-line toolmysql and select a database:

$> mysqlyour-database-name

To create and populate the example table, use these statements:

CREATE TABLE shop (    article INT UNSIGNED  DEFAULT '0000' NOT NULL,    dealer  CHAR(20)      DEFAULT ''     NOT NULL,    price   DECIMAL(16,2) DEFAULT '0.00' NOT NULL,    PRIMARY KEY(article, dealer));INSERT INTO shop VALUES    (1,'A',3.45),(1,'B',3.99),(2,'A',10.99),(3,'B',1.45),    (3,'C',1.69),(3,'D',1.25),(4,'D',19.95);

After issuing the statements, the table should have the following contents:

SELECT * FROM shop ORDER BY article;+---------+--------+-------+| article | dealer | price |+---------+--------+-------+|       1 | A      |  3.45 ||       1 | B      |  3.99 ||       2 | A      | 10.99 ||       3 | B      |  1.45 ||       3 | C      |  1.69 ||       3 | D      |  1.25 ||       4 | D      | 19.95 |+---------+--------+-------+