Business Intelligence
Power BI, DAX, Power Query, KPI design, interactive dashboards and executive reporting.
Data Analyst · Business Intelligence Analyst
I turn complex data into clear business decisions.
I’m Ernest-Cyril Divine Onyeze. I clean, model and visualise data to uncover the patterns leaders need to act with confidence.
Power BIInteractive reporting
SQL + ExcelAnalysis & preparation
PythonData workflows
Open to data opportunities
01Featured case studyGlobal sales intelligence
DATA CLEANING ✦ DATA MODELLING ✦ DASHBOARD DESIGN ✦ BUSINESS INTELLIGENCE ✦ INSIGHT COMMUNICATION ✦
01 / About
Analysis built for the person who has to make the next decision.
I am a Data Analyst and Business Intelligence Analyst with a background in Software Engineering. I use Power BI, SQL, Excel and Python to transform raw information into reliable models, intuitive dashboards and practical recommendations.
My approach combines analytical rigour with clear visual communication. I care about data quality, meaningful metrics and making every report easy to explore—not just impressive to look at.
View my full CV ↗02 / Toolkit
Data Analysis
Excel, SQL, Python, exploratory analysis, data cleaning and insight development.
Data Modelling
Star schemas, relationships, date dimensions, calculated measures and model optimisation.
Communication
Data storytelling, stakeholder-focused design, documentation and actionable recommendations.
03 / Selected work
Featured Power BI case study
NaijaMart Global Sales, Profitability & Shipping Performance
An end-to-end BI project that transforms 51,290 order-line records into a four-page decision-support dashboard.
One dataset. Several decisions.
NaijaMart needed a clear view of sales growth, product profitability, customer and market performance, and shipping efficiency. The source data required cleaning, date correction and dimensional modelling before it could support reliable analysis.
My approach- Cleaned and transformed the source workbook in Power Query.
- Designed a star schema with sales, customer, product, location, market and date tables.
- Built reusable DAX measures for sales, profit, margin, growth, loss and shipping.
- Designed four connected report pages with slicers, navigation and contextual tooltips.
04 / Upcoming projects
Portfolio roadmap
New analysis projects in development.
The next releases will extend this portfolio beyond Power BI into SQL investigation and Excel-based financial and operational modelling.
02In development
SQL · Exploratory analysis
Customer Churn Deep-Dive
A query-led investigation using joins, CTEs, subqueries and window functions to identify churn patterns, high-risk customer groups and retention opportunities.
- Documented business questions and SQL scripts
- Churn drivers and customer-segment findings
- Reproducible GitHub case study
03Planned
Excel · Financial modelling
Financial and Operations Forecasting Model
An interactive Excel model for budgeting, scenario analysis and performance tracking using advanced formulas, PivotTables and management-ready summaries.
- Budget versus actual performance
- Forecast assumptions and scenario controls
- Operational KPI dashboard
05 / Process
01
Understand
Define the business questions and identify the decisions the analysis must support.
02
Prepare
Profile, clean and validate the data before designing a dependable model.
03
Analyse
Create meaningful measures and investigate the patterns behind performance.
04
Communicate
Deliver a clear, interactive story with findings people can act on.
Available for opportunities
Have a data problem worth solving?
I’m open to Data Analyst and Business Intelligence Analyst roles, collaborations and thoughtful conversations about data.