What is MySQL

MySQL is a database. A database defines a structure for storing information.

In a database, there are tables. Just like HTML tables, database tables contain rows, columns, and cells.

Databases are useful when storing information categorically. A company may have a database with the following tables: "Employees", "Products", "Customers" and "Orders".

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Database Tables

A database most often contains one or more tables. Each table has a name (e.g. "Customers" or "Orders"). Each table contains records (rows) with data.

Below is an example of a table called "Persons":

LastName	FirstName	Address	City
Hansen	Ola	Timoteivn 10	Sandnes
Svendson	Tove	Borgvn 23	Sandnes
Pettersen	Kari	Storgt 20	Stavanger

The table above contains three records (one for each person) and four columns (LastName, FirstName, Address, and City).

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Queries

A query is a question or a request.

With MySQL, we can query a database for specific information and have a recordset returned.

Look at the following query:

SELECT LastName FROM Persons

The query above selects all the data in the LastName column in the Persons table, and will return a recordset like this:

LastName
Hansen
Svendson
Pettersen