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Former Project · First Case Study

Data-Driven Business Case:
SQL + Tableau

MySQL Workbench Tableau Relational Modeling Business Analysis

This was my first real data project — a case study using MySQL and Tableau to answer a business question for a real-world scenario. I built a 9-table relational analysis from scratch, wrote every query by hand, and made my first dashboards. It's not polished, and I'd do some things differently now, but I'm proud of how far the analysis actually went.

The Scenario

Should Eniac partner with Magist to enter Brazil?

Eniac — the client

A Spain-founded marketplace known for premium Apple products and curated accessories, exploring expansion into Brazil.

Magist — the candidate

A Brazilian SaaS platform connecting small and medium stores to major marketplaces, also handling warehousing, shipping, and customer service on sellers' behalf.

Q1Is Magist specialized in selling high-end tech products?
Q2Are deliveries fast enough — and are customers satisfied?
Getting Started

Understanding the data

Before answering anything, I had to understand what I was working with: a snapshot database with 9 linked tables — orders, customers, sellers, products, payments, reviews, geolocation, and category translations. Mapping this out first made every query afterward much easier to write correctly.

EER diagram of the 9-table Magist database schema
EER diagram — orders sits at the center, joined out to customers, sellers, order items, payments, and reviews.
99,441
total orders
32,951
products
3,095
sellers
96.5%
orders delivered
Getting Further

Four findings

01

Not a high-end tech specialist

I flagged five categories as "high-tech": computers, computer accessories, tablets/printing, telephony, and watches/gifts. Computers make up just 0.21% of orders (203 out of ~99k) — but they carry the highest average price ($1,053) and the best customer reviews of any tech category.

Bar chart comparing average price and order count across tech categories
Average price vs. order count by tech category — computers are rare, but priced and rated the best.
VerdictMagist isn't a premium-tech specialist today — but where they do carry tech, it performs well.
02

Delivery is a genuine strength

Across every tech category, the overwhelming majority of orders arrive before the estimated delivery date — between 88% and 96%, depending on category.

Table showing delivery timing breakdown by tech category
Delivery timing by category — "earlier" dominates in every case.
VerdictFulfillment is reliable, not a risk factor for a potential partnership.
03

The revenue gap

Tech categories are a minority of Magist's business, but not a trivial one.

$16.0M
total platform revenue
$3.79M
tech category revenue
~24%
tech share of revenue
VerdictTech is a real, established slice of the business — enough to build on, not enough to call Magist a specialist.
04

Geography matters for expansion

Orders and revenue are heavily concentrated in São Paulo and the southeast — exactly where Eniac would want the strongest overlap if entering the market.

Map of Brazil showing order count and revenue by state
Orders & revenue by state — São Paulo alone accounts for the largest share of both.
Conclusion

My take

"Magist isn't currently a high-end tech specialist, but their delivery performance and product quality in the categories they do carry suggest they could support Eniac's premium catalog well. I'd want to understand the cancellation spikes at the edges of the dataset before fully trusting these numbers." — Iliya, on finishing this project
Under the Hood

Stack & approach

DatabaseMySQL Workbench — 9-table relational schema, hand-written joins and window functions
VisualizationTableau Public — geographic maps, bar charts, and breakdown tables
ScopeBusiness case analysis: partner evaluation for market expansion
What's nextInvestigate the September/October 2018 cancellation spikes before trusting the full-period averages