Author: Tomas Zakarevičius

Learn when to use Unpivot and Pivot in Power Query – how to turn columns into rows and back, and how to avoid common mistakes.

Learn the difference between Merge and Append in Power Query – when to use which, Join types, key column cleanup, and common mistakes.

Learn the 6 most commonly used Power Query text cleanup steps – Trim, Replace Values, Extract, Split Column, Format, and Column From Examples.

Learn why Changed Type and Remove Columns steps in Power Query often cause errors when data refreshes, and how to make your transformations more stable.

Learn how the Power Query Editor works – Applied Steps, the Formula Bar, and M code. Understand the transformation chain and avoid common mistakes.

Learn what a proper dataset is for Power Query – headers, merged cells, data types, null values, and one cell, one value.

Learn how the Power Query Folder connector automatically combines multiple Excel or CSV files into one table, and how automatic refresh works.