· beginner
Power Query and Data Preparation
The half of Power BI that runs before a single measure does. Where cleaning belongs, how to reshape data into something a report can use, and why a refresh that took nine seconds now takes nine minutes.
Written in house, from the work rather than from a syllabus. Every example is one we would use ourselves, and every quiz question explains why its answer is right.
What you’ll learn
- Decide whether a transformation belongs in the source, Power Query or DAX
- Read a list of applied steps and predict what each one receives
- Unpivot wide data so a report survives the arrival of a new month
- Choose between merging and appending, and expand without multiplying rows
- Recognise what breaks query folding, and check whether it is still happening
- Set types deliberately so a refresh fails loudly rather than silently
Before you start
- · Comfort with a table of records and the idea of a join
- · No prior Power Query or M