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.