For the first week, the solution was pretty straight forward. Nevertheless, there were still some learning points for me!
1. When creating a calculated field in Prep, you cannot use the SUM function. I vaguely remember being taught this at the data school but I hadn’t used Prep for quite a while – so I forgot!
To get around this problem, you have to use the “Aggregate step” in Prep, where you choose which fields to group by and which ones to aggregate.
2. In your “Aggregate step”, you can also create a calculated field. This was helpful to limit the amount of steps I used in my workflow.
Try the challenge for yourself here: