In today’s data-driven business environment, SQL is the foundational skill for extracting value from data. Proficiency in SQL enables you to:
- Transform raw data into actionable insights
- Automate and streamline reporting processes
- Support data-driven decision-making with precision
- Enhance career opportunities in analytics, engineering, and leadership
This document serves as a central directory for all SQL-related projects, case studies, and learning materials within this portfolio. Each entry is organized for easy navigation, with direct links to documentation, datasets, and SQL scripts.
A case study analyzing sales data for the "Balanced Tree" company, including query performance.
An analysis project focused on understanding and modeling car prices.
An exploratory data analysis correlating crime data with weather patterns in Chicago for the year 2021.
An analysis related to a company's departmental structure and data.
Analysis focusing on the characterization of a COVID-19 dataset.
A comprehensive analysis of universities offering Computer Science programs.
- Project Problem Statement
- Data & Dictionary
A popular SQL case study involving customer purchasing habits, pizza metrics, and business requirements at a diner.
- Project Overview (README)
- Contextual Pre-Read
- Business Requirements Document
- Danny's Diner Case Study Solution
- Pizza Metrics Analysis
Resources and exercises based on the 'Data Wrangling with SQL' book by Raghav Kandappa & Shivangi Saxena.
- Book PDF: Data Wrangling with SQL
- Exercise Files
- Amazon Interview Questions (SQL)
- Approved & Declined Transactions (SQL)
- Article Viewership (SQL)
- Books With Low Demand (SQL)
- Business Activity (SQL)
- Candidates With Most Votes (SQL)
- Deloitte Interview Question (SQL)
- Deloitte Interview Swapping Product ID (SQL)
- Employee With Second Biggest Salary (SQL)
- Games Played So Far (SQL)
- Highest Answer Rate (SQL)
- Median Salary (SQL)
- Swapping Departments Notes
- Unique SQL Prep Questions Notes
- Restaurant Database (SQLite)
- Sales & COGS Database (SQLite)
A project focused on database design, including schema for a social media platform clone (Facebook/Instagram).
- Full Database Schema
- Instagram Clone Database Schema
- Facebook User Table Schema
- Generic User Table Schema
- Post Identification Logic
- Product Diversification Notes
- Database Relationship Diagram (ERD)
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Reference material for working with MongoDB.
A project demonstrating data cleaning techniques on the Nashville housing dataset using SQL.
An analysis of public school test score data from New York City.
Analysis focused on the experience of runners and customers, likely for a delivery or service platform.
A project focusing on the database design and analysis of invoicing data from Sao Paulo.
A collection of foundational materials and scripts for learning SQL.
- 30 Days of SQL Guide (PDF)
- Generic Database Creation Script
- HR Database Creation Script
- Inventory Database Creation Script
- Store Database Creation Script
The classic interactive game designed to teach SQL concepts through a fun, problem-solving challenge.
A collection of practice problems, interview questions, and case studies to sharpen SQL skills.
- Amazon Interview Questions Walkthrough
- Customer Behavior Analysis Case Study
- Data Cleaning and Transformation Guide
- Guide to Joins & Window Functions
- General Interview Notes
- COVID-19 Practice Dataset
An exploratory data analysis of World Cup data, focusing on match and goal statistics.
- Real-world case studies covering:
- Sales performance analysis
- Customer behavior segmentation
- Operational efficiency tracking
- Financial and inventory reporting
- Industry-relevant datasets for hands-on practice.
- Prioritizes high-impact SQL techniques used by professionals.
- Concise, direct examples designed for rapid comprehension.
- Optimized query writing for performance and cost efficiency.
- Database design principles for scalability and reliability.
- Advanced analytical methods to solve complex business problems.
- Core SQL operations (
SELECT,WHERE,JOIN,GROUP BY) - Data manipulation (
INSERT,UPDATE,DELETE) - Essential business queries (revenue calculations, basic aggregations)
- Advanced filtering and subqueries
- Time-series analysis (trends, period-over-period comparisons)
- Query optimization and indexing strategies
- Window functions for rankings and running calculations
- Database normalization and schema design
- Handling large-scale datasets efficiently
- Begin with
/foundation– Master the critical SQL commands first. - Apply skills in
/business-cases– Solve real business problems. - Advance to
/advanced– Refine expertise with high-level techniques.
Traditional SQL training emphasizes syntax over application. This repository focuses on practical execution, ensuring that every concept learned translates directly to business value.
Start with /foundation/1_core_queries.md to write your first high-value SQL query.
- Submit pull requests with additional business-focused SQL examples.
- Share your progress and insights with the community.
SQL is not just a technical skill - it’s a competitive advantage. Start leveraging it now.