SQL Roadmap (Beginner → Advanced) - Textnotes

SQL Roadmap (Beginner → Advanced)

The SQL Roadmap provides a clear, step-by-step learning path to master database concepts—from basic queries and joins to advanced topics like indexing, stored procedures, optimization, and real-world projects. It helps learners build strong SQL skills for development, data analysis, and backend applications.

1) Introduction to Databases and SQL

Concepts:

  1. What is a database?
  2. Types: Relational (RDBMS) vs Non-relational (NoSQL)
  3. SQL vs NoSQL
  4. Database terminology: Tables, rows, columns, schema, primary key, foreign key
  5. Database design basics

Practical Tasks:

  1. Install MySQL / SQL Server / PostgreSQL / Oracle
  2. Create your first database and table
  3. Understand schema and relationships


2) Basics of SQL

Concepts:

  1. SQL syntax
  2. CRUD operations: Create, Read, Update, Delete
  3. Data types: INT, VARCHAR, DATE, DECIMAL, BOOLEAN

Commands to Learn:

  1. CREATE DATABASE, DROP DATABASE
  2. CREATE TABLE, ALTER TABLE, DROP TABLE
  3. INSERT INTO
  4. SELECT
  5. UPDATE
  6. DELETE

Practice:

  1. Create a table Employees with columns ID, Name, Department, Salary
  2. Insert, update, delete records
  3. Retrieve all records


3) Filtering and Sorting

Concepts:

  1. WHERE clause
  2. Comparison operators: =, <>, >, <, >=, <=
  3. Logical operators: AND, OR, NOT
  4. ORDER BY for sorting
  5. LIMIT / TOP to restrict results

Practice:

  1. Filter employees with salary > 50000
  2. Sort students by marks descending
  3. Filter with multiple conditions


4) Aggregate Functions and Grouping

Concepts:

  1. Aggregate functions: COUNT(), SUM(), AVG(), MIN(), MAX()
  2. Grouping: GROUP BY
  3. Filtering groups: HAVING

Practice:

  1. Count employees per department
  2. Average salary per department
  3. Departments with max/min salary


5) Joins and Relationships

Concepts:

  1. Types of joins:
  2. INNER JOIN
  3. LEFT JOIN
  4. RIGHT JOIN
  5. FULL OUTER JOIN
  6. CROSS JOIN
  7. Self-join
  8. Foreign key relationships

Practice:

  1. Join Employees and Departments
  2. List employees without departments
  3. List students with enrolled courses


6) Subqueries

Concepts:

  1. Subqueries in SELECT, FROM, WHERE
  2. Correlated vs non-correlated subqueries

Practice:

  1. Employees earning more than average
  2. Customers with highest purchases


7) Set Operations

Concepts:

  1. UNION / UNION ALL
  2. INTERSECT
  3. EXCEPT / MINUS

Practice:

  1. Merge two student tables
  2. Find common employees in two departments


8) Indexing and Performance

Concepts:

  1. What is an index?
  2. Types: Single column, Composite
  3. Clustered vs Non-clustered index
  4. Query optimization, execution plan

Practice:

  1. Create indexes on frequently queried columns
  2. Analyze query performance


9) Views

Concepts:

  1. What is a view
  2. Creating, updating, dropping views
  3. Advantages of views

Practice:

  1. Create a view of top 10 highest-paid employees
  2. Use views to simplify queries


10) Stored Procedures and Functions

Concepts:

  1. Stored procedures: creation, execution
  2. Functions: scalar, table-valued
  3. Input/output parameters
  4. Advantages of stored procedures

Practice:

  1. Procedure to fetch employee details by department
  2. Function to calculate tax on salary


11) Triggers

Concepts:

  1. What are triggers
  2. Types: BEFORE INSERT, AFTER UPDATE, BEFORE DELETE
  3. Use cases: audit, logging, validation

Practice:

  1. Trigger to log updates in employee table
  2. Trigger to prevent salary decrease


12) Transactions

Concepts:

  1. BEGIN, COMMIT, ROLLBACK
  2. ACID properties
  3. Savepoints

Practice:

  1. Implement transaction for transferring money between accounts
  2. Rollback in case of error


13) Advanced SQL Queries

Concepts:

  1. Window functions: ROW_NUMBER(), RANK(), DENSE_RANK(), NTILE()
  2. CTE (Common Table Expressions)
  3. Recursive queries
  4. Pivot / Unpivot data

Practice:

  1. Rank employees by salary in each department
  2. Use CTE for hierarchical data
  3. Pivot sales data per month


14) Data Types and Constraints

Concepts:

  1. Constraints: PRIMARY KEY, FOREIGN KEY, UNIQUE, NOT NULL, CHECK
  2. Default values
  3. Identity / Auto-increment columns

Practice:

  1. Add constraints to employees table
  2. Ensure uniqueness and data integrity


15) Advanced Data Handling

Concepts:

  1. Temporary tables
  2. Table variables
  3. Bulk insert operations
  4. Data import/export (CSV, JSON)

Practice:

  1. Create temp table for processing
  2. Bulk insert multiple records


16) Security and Permissions

Concepts:

  1. Roles and users
  2. GRANT / REVOKE
  3. Views and stored procedures for security
  4. SQL injection prevention

Practice:

  1. Create users with read-only access
  2. Prevent SQL injection using parameterized queries


17) Backup and Recovery

Concepts:

  1. Full backup, differential backup, transaction log backup
  2. Restore database
  3. Point-in-time recovery

Practice:

  1. Backup a database
  2. Restore to a new database


18) Advanced Optimization

Concepts:

  1. Query tuning
  2. Index maintenance
  3. Execution plans
  4. Partitioning tables
  5. Materialized views

Practice:

  1. Analyze and optimize slow queries
  2. Use partitioning for large tables


19) SQL for Analytics

Concepts:

  1. Advanced grouping: GROUPING SETS, ROLLUP, CUBE
  2. Ranking and windowing functions
  3. Date and string functions
  4. Reporting queries

Practice:

  1. Sales analysis by region and quarter
  2. Running totals and moving averages


20) NoSQL & Big Data SQL Concepts (Optional)

Concepts:

  1. SQL-like querying in NoSQL databases
  2. HiveQL / BigQuery SQL
  3. Integration with Python / R for analytics

Practice:

  1. Query JSON / document data in SQL
  2. Aggregate large datasets