Summary  
This chapter covers data loading and transformation techniques—including validating and converting data types, renaming columns, filtering rows, replacing incorrect values, and adding conditional columns—to prepare datasets for analysis.  

General domain of usage  
Data preparation and ETL processes

The solution walkthrough for loading and cleaning the data. After attempting the build on your own, watch this chapter to compare your approach with the reference solution. You will load all four files into Power Query and complete three data preparation steps: fix a data quality issue in the Sales Discount column, filter out return rows where Quantity is negative, and add a Product Line column to the Category Lookup table that flags each category as Expansion or Legacy. 


Master the skills needed to turn raw data into professional, interactive reports using Power BI. You'll connect to data sources, clean and transform data with Power Query, build data models, write DAX measures, and publish polished dashboards to Power BI Service. No prior experience required.

Get hands-on experience with Power BI Desktop: understand where it fits in the modern data stack, install it, explore the interface, connect to your first dataset, and build your first bar chart.

Master the skills needed to clean, transform, and combine data using Power Query – from filtering rows and adding columns to merging tables and reshaping data with pivot operations.

Explore the essentials of relational data modeling and DAX – build star schemas, define relationships, write measures, and use time intelligence functions to answer real business questions.

Dive into the fundamentals of Power BI visuals – choose the right chart type, configure slicers and filters, add drillthrough navigation, and create bookmark-driven interactive experiences.

Transform the way you present data by applying layout and design principles, building multi-page reports, setting up row-level security, and publishing to Power BI Service with scheduled refresh.

Gain a solid understanding of the end-to-end Power BI workflow by completing a guided project – from data preparation and modeling to building a multi-page dashboard and publishing it to the Service.

Loading the Data