Mihaylo Melnik

My Github: https://github.com/msmelnyk

I work with data analytics, Power BI reporting, SQL queries, data preparation, and reporting automation.

I help businesses organize their data, build clear dashboards, automate manual reports, and get the right metrics faster for better decision-making.

Main areas I can help with:

Power BI and Business Reporting

• development of interactive Power BI dashboards;
• setup of KPIs, metrics, filters, slicers, and visualizations;
• connecting data from Excel, Google Sheets, SQL Server, PostgreSQL, BigQuery, and other sources;
• creating DAX measures and business calculations;
• fixing issues in existing Power BI reports;
• optimizing report structure and data models;
• preparing reports for sales, marketing, finance, operations, internal analytics, and management reporting.

SQL, Databases, and Data Preparation

• writing SQL queries for PostgreSQL, SQL Server, and BigQuery;
• data selection, aggregation, metric calculation, JOINs, CTEs, and window functions;
• preparing data for reporting and analytics;
• finding duplicates, cleaning data, and checking data quality;
• optimizing slow SQL queries;
• creating simple reporting data marts;
• helping with calculation logic and data accuracy checks.

Reporting Automation and Python

• automation of manual data-related tasks;
• processing large dataset;
• scripts for regular data preparation;
• data loading and transformation;
• ETL scripts;
• working with APIs, files, and databases;
• automating routine tasks that are currently done manually.

BI / Data Support

• support for existing reports and dashboards;
• fixing data refresh issues;
• checking incorrect metrics;
• consulting on report structure and calculation logic;
• helping users understand and work with reports;
• improving and extending existing BI solutions.

Website and Marketing Analytics

• analysis of GA4 / BigQuery data;
• building reports for website traffic, events, clicks, and conversions;
• calculating CTR, sessions, users, events, and other metrics;
• visualizing marketing and product metrics in Power BI.

I work carefully with data: first I clarify the task and business logic, then I propose a clear and practical solution. I can help with both small one-time tasks and full reporting or automation projects.

Tech stack: Power BI, DAX, SQL, PostgreSQL, SQL Server, BigQuery, Python,  Power Query,  ETL/ELT.