What is SQL

• SQL stands for Structured Query Language. It is a standard programming language used for managing and manipulating relational databases. Developed in the 1970s, SQL allows users to access, insert, update, and delete data in a database, as well as define the structure and relationships between different database tables.

Here are some key aspects of SQL:

• Database Management System (DBMS): SQL is not a standalone application but rather a language used to interact with database management systems such as MySQL, PostgreSQL, Oracle, SQL Server, SQLite, and others. These DBMSs handle the storage, retrieval, and management of data based on the SQL commands.

• Relational Databases: SQL is specifically designed for relational databases, which store data in tables with predefined columns and data types. These tables are related to each other using keys, allowing for efficient data retrieval and manipulation.

• Data Manipulation: SQL provides commands to perform various operations on data, such as querying (SELECT), inserting new records (INSERT), updating existing records (UPDATE), deleting records (DELETE), and more.

• Data Definition: SQL also includes commands for defining the database structure. These commands are used to create and modify database objects, such as tables (CREATE TABLE), views (CREATE VIEW), and indexes (CREATE INDEX).

• Data Control: SQL includes commands for managing user access rights and permissions on the database, ensuring data security and integrity.

Here's a simple example of an SQL query that retrieves data from a fictional "employees" table:

    SELECT first_name, last_name, department

    FROM employees

    WHERE department = 'Human Resources';

• In this query, we are selecting the "first_name," "last_name," and "department" columns from the "employees" table where the "department" column matches 'Human Resources'.

• SQL is widely used across the industry and is an essential tool for anyone involved in working with relational databases, from database administrators and developers to data analysts and business intelligence professionals. Its declarative nature allows users to specify what data they want to retrieve or manipulate, leaving the database engine to figure out the most efficient way to carry out the request.