COVID-19 Data Exploration with SQL

Project Overview

This project analyzes global COVID-19 data using SQL Server Management Studio. It calculates total cases, deaths, death percentages, and vaccination trends, from individual countries up to global totals. Detailed comments in the SQL script explain query logic, handle edge cases (like zero values), and demonstrate an in-depth understanding of SQL operations.

Key Features

• Collects and imports COVID-19 datasets: CovidDeaths and CovidVaccinations.
• Calculates death percentages, total cases, and total deaths for countries and global aggregation.
• Analyzes population vs. infection rates and identifies trends across continents and worldwide.
• Computes cumulative vaccination doses using window functions and running totals.
• Handles zero values and nulls to prevent errors in calculations.
• Uses decimal and float conversions for precise percentage calculations.
• Includes detailed comments and explanations in the SQL script for better understanding.

Data Analysis Highlights

• Country-to-global COVID case and death trends.
• Population-adjusted infection and death percentages.
• Vaccination coverage trends over time, with cumulative doses.
• Use of partitioning and cumulative sums to track vaccine rollout efficiently.

Technical Details

• All queries executed in SQL Server Management Studio (SSMS).
• Demonstrates proficiency in:
  • Conditional logic (CASE statements)
  • Aggregations (SUM, MAX, MIN)
  • Window functions (OVER, PARTITION BY)
  • Data type casting (FLOAT, DECIMAL)
  • Handling missing or zero data gracefully

How to Use

1. Clone or download the repository.
2. Open SQL Server Management Studio (SSMS).
3. Execute Covid19_Data_Analysis.sql to explore all queries and examples.
4. Review detailed comments to understand the logic and reasoning behind each query.

Why This Project Matters

• Demonstrates the ability to analyze large datasets from multiple angles.
• Shows skill in handling edge cases, precise calculations, and cumulative metrics.
• Enhances data-driven thinking and problem-solving with real-world data.
• Provides a comprehensive SQL learning resource for anyone studying COVID trends or database analytics.

Notes

• All calculations remain precise even when values are zero or missing.
• Queries are structured for clarity and readability, making it easy for others to learn from my work.
• Comments in the SQL script include step-by-step examples and explanations for deeper understanding.