🔰 SQL Fundamentals

What is SQL & where it is used

Databases vs DBMS

Relational databases overview

SQL syntax & conventions

🏗 Database Basics

Tables, rows, columns

Primary key & foreign key

Data types (INT, VARCHAR, DATE, etc.)

Creating databases & tables

📝 Data Definition Language (DDL)

CREATE

ALTER

DROP

TRUNCATE

Constraints (NOT NULL, UNIQUE, CHECK, DEFAULT)

✏️ Data Manipulation Language (DML)

INSERT

UPDATE

DELETE

SELECT basics

WHERE clause

🔍 Data Querying & Filtering

SELECT with conditions

AND / OR / NOT

BETWEEN

IN

LIKE

IS NULL

📐 Sorting & Limiting Data

ORDER BY

LIMIT / OFFSET

DISTINCT

🔗 SQL Joins (Very Important)

INNER JOIN

LEFT JOIN

RIGHT JOIN

FULL JOIN

Self Join

Join multiple tables

📊 Aggregate Functions

COUNT

SUM

AVG

MIN / MAX

GROUP BY

HAVING

🧠 Subqueries & Nested Queries

Subqueries in SELECT

Subqueries in WHERE

Correlated subqueries

🧾 Views & Indexes

Creating & using views

Indexes & performance basics

When to use indexes

🔐 Constraints & Keys

Primary key

Foreign key

Unique constraints

Referential integrity

🔄 Transactions

COMMIT

ROLLBACK

SAVEPOINT

ACID properties

⚙️ Advanced SQL Concepts

CASE statements

COALESCE & NULL handling

Window functions (ROW_NUMBER, RANK, DENSE_RANK)

Common Table Expressions (CTEs – WITH clause)

⚡ Performance & Optimization (Intro)

Query execution basics

Index usage

Writing efficient queries

🧑‍💻 SQL with Real-World Scenarios

Employee & company databases

E-commerce use cases

Analytics-style queries

🎯 Interview Preparation

Most-asked SQL interview questions

Query-writing practice

Problem-solving approach

SQL tricks used in interviews

🏆 Bonus (Career Support)

SQL for backend developers

SQL for data roles

Resume & LinkedIn guidance

How SQL is used in real companies