Mastering Power Query in Power BI: A Complete Data Transformation Guide

Power Query is the backbone of data preparation in Power BI. Before you can build stunning dashboards or write complex DAX, your data needs to be clean, consistently shaped, and properly related. In this guide, we'll use the real CodeSphere Hub dataset, comprising sales transactions, booking records, product info, and calendar data, to demonstrate every essential Power Query technique. The dataset includes 163,000+ sales rows spanning 2015–2020, a messy hotel bookings CSV full of nulls and incon