π Case Study: Vehicle Repair Shop Data Analysis
π Objective
The goal of this project was to analyze customer behavior, vehicle patterns, job performance, parts usage, and financial metrics for a vehicle repair shop. Using SQL, I created queries that answered key business questions and revealed actionable insights for growth and efficiency.
π§ Data Preparation
- Cleaned and standardized multiple CSV files.
- Ensured consistency in categorical data (e.g., vehicle makes).
- Indexed frequently queried columns for faster performance.
- Imported the data into a relational database.
π SQL Files & Setup:

π₯ Customer Analysis
SQL Techniques Used:
- Aggregation Queries (SUM, AVG) β to calculate spend and averages.
- Sorting & LIMIT β to find top 5 spenders.
- COUNT & GROUP BY β to track visit frequency.
Findings:
- Jennifer Robinson was the top spender ($1802.21).
- Average customer spend: $177.79.
- Repeat customers showed patterns in service frequency.
π Vehicle Analysis
SQL Techniques Used:
- AVG() β to calculate vehicle mileage.
- GROUP BY + COUNT() β to find most common makes/models.
- CASE WHEN + GROUPING β to segment vehicles by age.
Findings:
- Average mileage: 33,699 miles.
- Common models: BMW X5, Toyota Corolla, Honda Civic.
- Older vehicles required more frequent major repairs.
π Job Performance Analysis
SQL Techniques Used:
- JOINs β to connect jobs with revenue data.
- SUM() & GROUP BY β to calculate revenue by job type.
- ORDER BY + LIMIT β to find highest and lowest cost jobs.
Findings:
- High revenue jobs: Replace front CV Axel ($437.50) & Transmission check ($300.00).
- Underperforming services: Replace air filter.
π© Parts Usage Analysis
SQL Techniques Used:
- TOP N Queries (LIMIT) β to list most used parts.
- AVG() & SUM() β to calculate part costs and revenue.
Findings:
- Most used parts: CV Axel, Brake Pads, Battery.
- Average part cost highlighted stock planning needs.
π° Financial Analysis
SQL Techniques Used:
- Date Functions (MONTH, YEAR) β to track monthly revenue.
- SUM() & CASE WHEN β to split labor vs. parts revenue.
- Profitability Calculation using revenue β costs.
Findings:
- Monthly revenue: $3954.86.
- Profitability: $2163.96.
- Sales tax had a measurable impact on net revenue.
π SQL Queries:
π Key Insights
- Top customers drive revenueβopportunity for loyalty programs.
- Stocking high-demand parts prevents delays.
- Bundling low-revenue jobs could increase sales.
- Prioritize scheduling high-profit jobs.
π Recommendations
- Launch a customer loyalty program for repeat spenders.
- Improve stock management of high-demand parts.
- Bundle low-revenue jobs to boost sales.
- Focus marketing on high-margin but low-frequency services.