Set up the database
Created a car schema in PostgreSQL with four tables and primary keys, then loaded the data.
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Tableau · PostgreSQL
Car Sales Analysis
Two years of car sales stored in PostgreSQL and brought to life in Tableau: which makes, states, dealerships and customers drive the revenue?
$528MTotal sales
10,000Transactions
200Unique customers
$52.8KAverage sale price
The data
Four related tables
Every sale in transactions points to one customer, one dealership and one vehicle.
- customer_id
- name
- phone
- address
- dealership_id
- name
- city
- state
- phone
- vin
- make
- model
- year
- color
- transaction_id
- date
- dealership_id → dealerships
- customer_id → customers
- vin → vehicles
- price
Walkthrough
How I built it, step by step
Connect Tableau to PostgreSQL
Joined the four tables on customer_id, dealership_id and vin.
Why: one joined view lets a single sheet use fields from any table.
Build the KPI sheets
Four headline numbers: Total Sales, Total Transactions, Unique Customers and Average Price per Vehicle.
Build the "who and where" sheets
Top Makes, Top States, Top Dealerships, Top Customers and Most Popular Colours, each ranking by sales or by number of transactions.
Add the time view
A Monthly Sales Trend and a Sales and Revenue Rate sheet to show how sales moved over time.
Assemble the dashboard
Arranged the sheets into one dashboard, with the KPIs on top and the rankings below.
The dashboard
Explore it yourself
Inside the workbook
The 11 sheets
KPIs
Total SalesTotal TransactionsUnique CustomersAvg Price / Vehicle
Rankings
Top MakesTop StatesTop DealershipsTop Customers
Patterns
Monthly Sales TrendSales & Revenue RateMost Popular Colours
Findings
What stands out
Figures calculated from the PostgreSQL data.
🗺️ Washington leads by a distance
Washington brings in $82.7M, about 52% more than second-placed South Carolina ($54.6M). Michigan follows with $50.1M.
🚘 Mazda tops the makes
Mazda earned $18.1M from 339 sales, ahead of Genesis ($15.4M) and Buick ($14.9M).
🏬 Revenue is spread across dealerships
The top three dealerships are close: Thornton, Thomas and Kennedy ($28.5M), Martin Group ($27.9M) and Willis, Salazar and Sanchez ($27.7M).
🎨 SkyBlue is the most-sold colour
SkyBlue appears in 182 sales, followed by HotPink (169) and Maroon (165).
Project files