Structured Query Language (SQL)

What is SQL?

SQL (Structured Query Language) is the standard language used to manage and manipulate relational databases. It is used to create, read, update, and delete data in databases like MySQL, PostgreSQL, Oracle, and SQL Server.

Why Use SQL?

• Standardized and widely adopted across database systems
• Provides powerful commands for data manipulation
• Efficiently handles large amounts of structured data
• Used in almost all full stack web applications with relational data

Key SQL Operations

• SELECT: Retrieve data from tables
• INSERT: Add new data into tables
• UPDATE: Modify existing data
• DELETE: Remove data from tables
• CREATE: Create new tables or databases
• DROP: Delete tables or databases

Types of SQL Commands

• DML (Data Manipulation Language): SELECT, INSERT, UPDATE, DELETE
• DDL (Data Definition Language): CREATE, DROP, ALTER
• DCL (Data Control Language): GRANT, REVOKE
• TCL (Transaction Control Language): COMMIT, ROLLBACK

Example SQL Query

SELECT name, age FROM students WHERE age > 18;

Advantages of SQL

• Easy to learn and use
• Handles complex queries efficiently
• Ensures data integrity and security
• Widely supported by relational database systems

Limitations

• Not suitable for unstructured or semi-structured data
• May be complex when working with very large databases without optimization

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