Data Analyst Portfolio Project

A collection of SQL projects demonstrating data cleaning and exploratory data analysis skills, using T-SQL (SQL Server).

Projects

1. COVID-19 Data Exploration (Covid19_Project.sql)

Exploratory analysis of global COVID-19 cases, deaths, and vaccinations data.

• Infection and death rates by country and continent
• Countries ranked by highest infection rate relative to population
• Global daily case and death totals
• Rolling count of vaccinated population using window functions (SUM() OVER (PARTITION BY ...))
• CTEs and temp tables used to calculate vaccination percentage per population

Dataset: CovidVaccinations.xlsx

2. Nashville Housing Data Cleaning (data_cleaning_nashvillehousing.sql)

Data cleaning project on a raw Nashville housing dataset.

• Standardized inconsistent date formats
• Populated missing property addresses using a self-join on ParcelID
• Split address fields into individual columns (address, city, state)
• Removed duplicate records
• Normalized categorical values (e.g. Y/N to Yes/No)

Skills demonstrated

SQL Server (T-SQL), joins, window functions, CTEs, data cleaning, data standardization, exploratory data analysis.

Author

Idens Méranvil - Supply Chain Team Lead learning data analysis (SQL, Power BI, Python).