Introduction

SQL, which stands for Structured Query Language, is a programming language that is used to communicate with and manage databases. SQL is a standard language for manipulating data held in relational database management systems (RDBMS), or for stream processing in a relational data stream management system (RDSMS). It was first developed in the 1970s by IBM.

SQL consists of several components, each serving their own unique purpose in database communication:

• Queries: This is the component that allows you to retrieve data from a database. The SELECT statement is most commonly used for this purpose.
• Data Definition Language (DDL): It lets you to create, alter, or delete databases and their related objects like tables, views, etc. Commands include CREATE, ALTER, DROP, and TRUNCATE.
• Data Manipulation Language (DML): It lets you manage data within database objects. These commands include SELECT, INSERT, UPDATE, and DELETE.
• Data Control Language (DCL): It includes commands like GRANT and REVOKE, which primarily deal with rights, permissions and other control-level management tasks for the database system.

SQL databases come in a number of forms, such as Oracle Database, Microsoft SQL Server, and MySQL. Despite their many differences, all SQL databases utilise the same language commands - SQL.

Learn more about SQL from the following resources:

• SQL Tutorial - Mode
• SQL Tutorial
• SQL Tutorial - W3Schools