Supermarket Sales and Customer Insights Dashboard — A Practical Power BI Project Guide.

Source: Dev.to

Project Overview

This technical article walks you step‑by‑step through a beginner‑friendly Power BI project using a real‑world supermarket transactions dataset. By the end of this guide, you will know where to download the data, how to prepare it, and how to build an interactive dashboard that answers real business questions.

You will act as a Junior Data Analyst, converting raw transaction records into insights that business stakeholders can explore without using spreadsheets.

Dataset Download

• 📌 Download the dataset

Dataset contents

• Three years of supermarket transaction data
• Multiple store locations (Australia)
• Individual transaction‑level records

Key columns

• Product Name
• Quantity Sold
• Total Sales Amount
• Payment Method
• Customer Type (Member / Non‑Member)
• Store Location
• Transaction Date

Business Questions This Project Answers

Before opening Power BI, understand the questions the dashboard should answer.

1. Sales Performance

• What is the total sales amount across all stores?
• How do sales trend over time (monthly and yearly)?

2. Product Analysis

• Which products generate the highest revenue?
• How do apple sales compare across different payment methods?

3. Customer Behavior

• How much do members vs non‑members spend?
• Which customer type contributes more to total revenue?

4. Payment Method Insights

• Which payment method is used most frequently?
• How does revenue differ by payment method?

5. Store Performance

• Which store location generates the highest sales?
• How does customer behavior vary by store?

These questions will guide every step of the analysis.

Step 1: Load the Data into Power BI

1. Open Power BI Desktop.
2. Click Get Data → Text/CSV.
3. Select supermarket_transactions.csv.
4. Load the data into Power BI.
5. Review column names and preview the data.

At this stage, do not build visuals yet. First, ensure the data is correct.

Step 2: Data Cleaning in Power Query

1. Open Transform Data to enter Power Query.
2. Perform the following actions:
   • Remove unnecessary or duplicate columns.
   • Fix incorrect data types:
     • Dates → Date
     • Sales & Quantity → Decimal / Whole Number
   • Rename columns for clarity (e.g., Total Sales Amount).
   • Check for missing or inconsistent values.

⚠️ Clean data is critical. Poor data quality leads to misleading dashboards.

Step 3: Data Modeling

• Confirm all columns have correct data types.
• Ensure the table structure is logical.
• No complex relationships are required for this project (single‑table model).

This project focuses on analysis and visualization, not complex modeling.

Step 4: Create Beginner‑Level DAX Measures

Create the following measures in Model view or Report view:

Total Sales =
SUM(supermarket_transactions[Total Sales Amount])

Total Quantity Sold =
SUM(supermarket_transactions[Quantity])

Average Transaction Value =
AVERAGE(supermarket_transactions[Total Sales Amount])

Sales by Customer Type =
SUM(supermarket_transactions[Total Sales Amount])

⚠️ These measures will power your KPI cards and charts.

Step 5: Build the Power BI Dashboard

Create a 1–2 page interactive Power BI dashboard using the visuals listed below. The dashboard should be designed for business users, not technical users.

Required Visuals

KPI Cards

• Total Sales
• Total Quantity Sold
• Average Transaction Value

Charts

• Bar Chart: Sales by Product
• Bar Chart: Sales by Store Location
• Pie or Column Chart: Payment Method Distribution
• Line Chart: Sales Trend Over Time

Slicers

• Store Location
• Product
• Customer Type
• Date

🎯 Design Principle: The goal is clarity, not decoration. Every visual should answer a specific business question.

Step 6: Validate Your Results

Before submitting your work, verify the following:

• Confirm all totals match your Excel analysis.
• Test all slicers and filters for correct behavior.
• Check visual titles, labels, and number formatting.
• Ensure visuals respond correctly to user interactions.

Final Submission Checklist

• Record a 4‑minute walkthrough video using Loom that demonstrates a fully functional Power BI dashboard.
• Briefly explain:
  • The dataset used
  • Key visuals and filters
  • Main business insights and conclusions
• Upload the recording to Loom and copy the shareable link.
• Submit the Loom video link via WhatsApp to 0796 448 232.