Olena

OLENA PETROVA

Junior Data Analyst

Khmelnytskyi Region, Ukraine · Remote
Email: [відкрити контакти](див. вище в блоці «контактна інформація») · Phone: [відкрити контакти](див. вище в блоці «контактна інформація»)
LinkedIn: [відкрити контакти](див. вище в блоці «контактна інформація») · GitHub: github.com/Yolka1811

PROFESSIONAL SUMMARY

Data Analyst with a 15-year background in sales operations, financial reporting, and business process
automation, now transitioning into data analytics with hands-on experience in SQL, Python, and Power BI.
Experienced in turning business questions into analytical workflows, from PostgreSQL queries and data analysis
to interactive dashboards and business recommendations. Master's in Economic Cybernetics (Honors), with
strong business domain knowledge and a practical understanding of how data supports decision-making.

TECHNICAL SKILLS

SQL: PostgreSQL (CTEs, JOINs, aggregations, window functions)
Python: Pandas, NumPy
Visualization: Power BI (DAX measures, interactive dashboards)
Tools: Microsoft Excel (Pivot Tables), Git / GitHub

PROJECTS

Customer RFM Analysis — PostgreSQL · Python (Pandas, NumPy) · Power BI

• Segmented customers into four actionable groups (Champions, Loyal, Regular, At-Risk) using Recency–
Frequency–Monetary scoring with SQL CTEs and NTILE window functions.

• Found that Champions make up just 20% of customers but generate 53.5% of revenue, while At-Risk
customers are the largest group (35%) yet contribute only 7.4% — directing retention priorities.

• Reproduced the full SQL logic in Python (Pandas + NumPy) and validated that both implementations
produced identical results, ensuring analytical consistency.

• Delivered per-segment business recommendations via an interactive Power BI dashboard.

Sales Performance Analysis — PostgreSQL · Power BI (DAX)

• Analyzed ~6.3M in total sales revenue across product categories in PostgreSQL, using window functions
(LAG, AVG() OVER()) to calculate day-over-day trends and deviation from category averages.

• Found that Electronics generated ~64% of total revenue while Books contributed only ~4%, surfacing a
clear revenue-concentration risk.

• Built an interactive Power BI dashboard with KPI cards, category/date filters, and DAX measures for self-
service reporting.

• Documented analytical limitations (no marketing, seasonality, or demographic data), separating
observed trends from causal conclusions.

Customer Retention Analysis (In Progress) — PostgreSQL · Python (Pandas) · Power BI

• Building cohort-based retention and churn analysis to track customer behavior over time and calculate
retention metrics.

PROFESSIONAL EXPERIENCE

Data Analytics — Professional Development | 2024 – Present

• Completed Python Data Science training (Udemy), then focused my learning on Data Analytics with an
emphasis on SQL, Python/Pandas, and Power BI.

• Built end-to-end portfolio projects (SQL → Python → Power BI), from raw queries through to business
recommendations.

Deputy Director / Sales Manager | Toys Group LLC | Jan 2017 – Feb 2022

• Built monthly plan-vs-actual financial reports and inventory forecasts that informed purchasing and
production decisions across a multi-category product line.

• Authored technical requirements for CRM, ERP, and warehouse automation systems and coordinated
implementation with developers — bridging business needs and data structures.

• Led business process automation initiatives, standardizing how operational and sales data was captured
and reported.

• Coordinated cross-functional teams (office, accounting) and participated in recruitment and onboarding.

Office Manager / Sales Manager | Dream Makers LLC | Apr 2008 – Sep 2016

• Administered the company ERP and maintained the customer database, keeping data consistent across
sales operations.

• Prepared recurring operational and financial reports used for internal business decisions.

Merchandiser | Dream Makers LLC | Feb 2007 – Mar 2008

EDUCATION

Master's Degree, Economic Cybernetics — Graduated with Honors
National Technical University "Kharkiv Polytechnic Institute" · 2003 – 2009

LANGUAGES

Ukrainian — Native · English — A2+ (actively improving)