SQL — From Basics to Advanced
SQL — From Basics to Advanced (Complete Description)
SQL (Structured Query Language) is the standard language used to store, retrieve, manipulate, and analyze data in relational databases such as MySQL, PostgreSQL, SQL Server, Oracle, and SQLite. Mastering SQL from basics to advanced is essential for developers, data analysts, data engineers, DBAs, and cybersecurity professionals.
SQL Basics
Fundamentals needed to start working with databases:
What is SQL & RDBMS
Database, Tables, Rows, Columns
Data Types (INT, VARCHAR, DATE, BOOLEAN, etc.)
DDL Commands
CREATE, ALTER, DROP, TRUNCATE
DML Commands
INSERT, UPDATE, DELETE
DQL Commands
SELECT
Filtering & Sorting
WHERE, ORDER BY, LIMIT
Operators
Arithmetic, Comparison, Logical
Constraints
PRIMARY KEY, FOREIGN KEY, UNIQUE, NOT NULL, CHECK
Intermediate SQL
Data manipulation and relationships:
Joins
INNER, LEFT, RIGHT, FULL
Aggregate Functions
COUNT, SUM, AVG, MIN, MAX
GROUP BY & HAVING
Subqueries
Nested queries
Indexes
Performance optimization basics
Views
Virtual tables
Transactions
BEGIN, COMMIT, ROLLBACK
Normalization
1NF, 2NF, 3NF
NULL Handling
IS NULL, COALESCE
Advanced SQL
High-performance and enterprise-level SQL:
Advanced Joins & Subqueries
Common Table Expressions (CTE)
WITH clause
Window Functions
ROW_NUMBER, RANK, DENSE_RANK, OVER
Stored Procedures & Functions
Triggers
Indexes (Advanced)
Clustered vs Non-clustered
Query Optimization
Execution plans
Partitioning
Concurrency Control
Locks, Deadlocks
ACID Properties
Security
Users, Roles, Permissions
SQL Injection & Prevention
Backup & Recovery
SQL for Security & Real-World Use
SQL in Web Applications
Preventing SQL Injection
Auditing & Logging
Database Hardening
Role-Based Access Control (RBAC)