SQL Tutorial - SQL Query Reference

SQL (Structured Query Language) is a computer language aimed to store, manipulate, and query data stored in relational databases. The first incarnation of SQL appeared in 1974, when a group in IBM developed the first prototype of a relational database. The first commercial relational database was released by Relational Software (later becoming Oracle).

Standards for SQL exist. However, the SQL that can be used on each one of the major RDBMS today is in different flavors. This is due to two reasons: 1) the SQL command standard is fairly complex, and it is not practical to implement the entire standard, and 2) each database vendor needs a way to differentiate its product from others. In this tutorial, such differences are noted where appropriate.

This SQL programming help site lists commonly-used SQL statements, and is divided into the following sections:

• SQL Commands: Basic SQL statements for storing, retrieving, and manipulating data in a relational database.
• Table Manipulation: How SQL statements are used to manage tables inside the database.
• SQL String Functions: Common string functions used in SQL.
• SQL Date Functions: Common date functions used in SQL.
• Advanced SQL: Advanced SQL commands.
• SQL Syntax: A single page that lists the syntax for all the SQL commands in this tutorial.

For each command, the SQL syntax will first be presented and explained, followed by an example. By the end of this tutorial, you should have a good general understanding of the SQL syntax, and be able to write SQL queries using the correct syntax. My experience is that understanding the basics of SQL is much easier than mastering all the intricacies of this database language, and I hope you will reach the same conclusion as well.

If you are interested in how to retrieve data using SQL, we recommend that you start with the SQL Commands section. If you are interested in understanding how SQL can be used to manipulate database tables, we recommend that you start with the Table Manipulation section. If you are looking for help on a specific SQL command, you can use the Site Map to find the command you are looking for.

Okay, enough introduction. Bookmark this site now and start now to learn SQL!