SQL, PySpark & AWS Mastery Hub

Three complete interactive guides — pick a track and start learning. Every lesson has live examples, diagrams, and interview prep.

Choose Your Track

Zero to interview-ready. Click a track to open its full guide — every lesson is available from the home page, and every card goes directly to that lesson.

🐍 Python for PySpark • 10 Chapters

Python Basics for PySpark

Learn Python fundamentals for PySpark — data types, strings, collections, functions, OOP, regex and 3 mini projects with hands-on examples and real outputs.

10 chapters45+ topics~5 hrs
📘 SQL Mastery • 12 Chapters • 67 Topics

SQL Mastery

Learn SQL from Zero to Data Engineer interview level. From SELECT to Window Functions, Star Schema, and query optimization — all with the employees/departments practice DB.

67 topics15 phases~6 hrs
⚡ PySpark Guide • 9 Chapters • 75 Topics

PySpark Interview Guide

Understand Spark through visuals — RDD vs DataFrame, Catalyst, DAG/Stages/Tasks, Partitions, Joins (Broadcast/Sort-Merge), Salting, and real-world troubleshooting.

75 topics9 chapters~7 hrs
☁️ AWS Data Engineering • 8 Chapters • 39 Topics

AWS Data Engineering

S3 features & storage classes, security, Glue DynamicFrames & DPU workers, Lambda triggers, SCD, Redshift distribution & sort keys, Airflow DAGs.

39 topics8 chapters~5 hrs

Jump to Any Lesson

Direct links to particular lessons — click to go straight there.

SQL • Basics

SQL Basics — SELECT & WHERE

SELECT, WHERE, AND/OR/NOT, DISTINCT, ORDER BY

Go to lesson →
SQL • Joins

JOINs — Simple Table Data

INNER, LEFT, RIGHT, FULL OUTER, SELF, CROSS with 4×3 sample tables and expected outputs

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SQL • Window

Window Functions

ROW_NUMBER, RANK, DENSE_RANK, PARTITION BY, LAG/LEAD, Running Total

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SQL • Interview

Interview Mastery

Second Highest Salary, Employees Above Dept Avg, Framework & Cheat Sheet

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PySpark • Fundamentals

RDD vs DataFrame vs Dataset

Low-level RDD vs optimized DataFrame vs type-safe Dataset

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PySpark • Joins

Joins — Sample Tables & Outputs

Inner, Left, Right, Full Outer, Left Semi/Anti with Venn diagrams and result tables

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PySpark • Performance

Shuffle & Salting

Data Skew visualization, Salting technique, Cache/Persist, AQE

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PySpark • Interview

Real-World Interview Simulator

Slow jobs, OOM, Data Skew — 8-step scenario reveal

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AWS • S3

S3 — Features & Storage Classes

Scalable storage, 11x9 durability, Standard vs Intelligent-Tiering vs Glacier

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AWS • Glue

Glue — DynamicFrames & DPU

Data Catalog, Crawlers, DynamicFrames choice type, G.1X/G.2X workers

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AWS • Redshift

Redshift — MPP & Sort Keys

Leader/compute nodes, Columnar, Distribution (key/even/all), Compound vs Interleaved

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AWS • Airflow

Airflow — DAG & Operators

PythonOperator, S3KeySensor, Catchup vs DependsOnPast, vs Step Functions

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Python • Basics

Python Basics — Features & Variables

6 features with pipeline context, naming rules (deduped 3×), PEP8, comments vs docstrings

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Python • Strings

Data Types & String Methods

Slicing visuals, every string method with before/after, phone validation chain

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Python • Collections

Lists, Dicts, Sets

append vs extend, nested dict (Spark JSON), set unions

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Python • OOP

OOP — Encapsulation & Abstraction

BankAccount private balance, ABC rulebook, 5 inheritance types + MRO

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🔒 My Recap — Digital Forensics Firm Notes →

Quick access to Digital forensic.md — your Tamil Nadu firm plan (private, rendered nicely).