🦠 COVID-19 Data Exploration using SQL (SSMS)

A T-SQL project that imports raw COVID-19 Excel data into SQL Server and explores cases, deaths, and vaccinations across countries and continents.

Preview

Project Overview

I imported two Excel files into a new SQL Server database and wrote queries to answer simple questions:

• How likely is death if someone gets COVID in a country (for example, India)?
• What percentage of a country's population got infected?
• Which countries and continents had the highest death counts?
• How many people were vaccinated over time?

Key Insights

Based on data from 1 Jan 2020 to 30 Apr 2021 (210 countries, 81,060 rows):

Metric	Result
Global cases	about 150.6 million
Global deaths	about 3.18 million
Global death percentage	about 2.11%
Highest infection rate	Andorra, about 17.1% of its population
Highest death count	United States (576,232), then Brazil and Mexico
India death percentage	about 1.11% (19.2M cases, 211,853 deaths)

How It Was Built

1. Import: Used the SSMS Import and Export Wizard to load CovidDeaths.xlsx and CovidVaccinations.xlsx.
2. New database: Created a new database, PortfolioProject, and loaded both files as tables (CovidDeaths, CovidVaccinations).
3. Explore: Wrote T-SQL queries on each table, then joined them on location and date.
4. Store: Saved the final vaccination query as a view, PercentPopulationVaccinated, for later use in dashboards.

Source Data

SQL Skills Used

• SELECT, WHERE, GROUP BY, ORDER BY
• Aggregates: SUM, MAX
• JOIN across two tables
• Window function: SUM() OVER (PARTITION BY ... ORDER BY ...) for rolling vaccinations
• CTE (WITH PopVsVac)
• CAST / CONVERT, ROUND, FORMAT
• CREATE VIEW

Files Included

File	Description
COVID Portfolio Project Data Exploratory using SQL.sql	All T-SQL queries
CovidDeaths.xlsx	Cases, deaths, population (85,171 rows)
CovidVaccinations.xlsx	Vaccinations and tests (85,171 rows)
data table 1.png, data table 2.png	Source data previews
data exploration queries image.png	Queries running in SSMS
view in sql image.png	Output of the saved view

How to Use

1. Open SSMS and create a database named PortfolioProject.
2. Import both Excel files with Tasks > Import Data.
3. Open the .sql file and run the queries one by one.

Tools

Microsoft SQL Server, SQL Server Management Studio (SSMS), T-SQL, Excel

Author

Minhaj Khan Data Analyst | SQL · Power BI · databricks · Azure · Excel · Python

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