Web Primer

SQL Primer

SQL - Structured Query Language

SQL is the standard language for accessing and manipulating databases.

Common database management systems are: MySQL, SQL Server, Access, Oracle, Sybase, and DB2

Knowledge of SQL is invaluable for anyone who wants to store or retrieve data from a database.

What is SQL?

• SQL stands for Structured Query Language
• SQL allows you to access a database
• SQL is an ANSI standard computer language
• SQL can execute queries against a database
• SQL can retrieve data from a database
• SQL can insert new records in a database
• SQL can delete records from a database
• SQL can update records in a database
• SQL is easy to learn

SQL Database Tables

A database usually contains one or more tables. Each table is identified by a name (e.g. "Customers" or "Orders"). Tables contain records (rows) with data.

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

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

SQL Queries

With SQL, we can query a database and have a result set returned.

A query like this:

Gives a result set like this:

How to Learn SQL?

Study our Complete SQL tutorial