What is SQL?

SQL (Structured Query Language) is the standard programming language for communicating with relational database systems. SQL lets us create, read, update, and delete data in a database.

A Brief History

SQL was first developed by a team at IBM in the 1970s. The language was originally named SEQUEL (Structured English Query Language) and was designed to access data stored in IBM's System R database system.

In 1986, SQL became an official standard of the American National Standards Institute (ANSI). Then, in 1987, the International Organization for Standardization (ISO) also adopted it as an international standard.

Why Is SQL Important?

SQL is the foundation of almost every modern application that requires data storage and management. Here are some reasons why SQL matters:

• Universal — Almost all database systems support SQL
• Efficient — Can manage millions of records quickly
• Declarative — We describe what we want, not how to do it
• Scalable — Works for small projects up to large enterprises

SQL Is Not an RDBMS

It is important to understand that SQL is only a query language, not a database system itself. An RDBMS (Relational Database Management System) is the software that uses SQL as its primary language.

Popular RDBMS examples:

SQL Dialects

Each RDBMS has its own variation or "dialect" of SQL. Although the SQL basics are the same, there are small differences in syntax and certain features.

-- Example: LIMIT in MySQL
SELECT * FROM student LIMIT 10;

-- Example: TOP in SQL Server
SELECT TOP 10 * FROM student;

-- Example: FETCH FIRST in PostgreSQL
SELECT * FROM student FETCH FIRST 10 ROWS ONLY;

All three queries above produce the same result — fetching 10 rows of data from the student table — but they are written in different syntax for each RDBMS.

Summary

SQL is the query language that has become the industry standard for managing relational data. Although each RDBMS has its own dialect, the SQL foundation remains the same. In this tutorial, we will use MySQL as the primary reference.

In the next chapter, we will learn the basic RDBMS concepts that underpin how data is stored and organized in a database.