#PreppinData 2024 wek 7:
The #PreppinData 2024 week 6 challenge was to find the latest salary per staff member and summarise their tax position given UK income tax bands.
We’re now into intermediary level challenges and so there are less prescriptive steps, and more options to solve the problem your way. For me the problem had two key parts: (1) get the latest row per staff member; and (2) the various calculations for salary and tax paid based on tax bands.
For part one I introduced an aggregage step to get the maximum row number per staff member, and then joined that back onto the input to return only the detals for that last row. I wondered if an alternative might have been to use a “level of detail” expression, with a filter, in a single step.
For part two I included all of the calculations in one “clean” step. I did hardcode the tax bands, and probably could have used a mapping table to allow for reuse in future years. I also hardcoded the sum of month  to , but perhaps could have found a way to allow for less months to be in the data set, in case the flow needed to be run mid-year.
The final week of beginner month for #PreppinData involved a bit more complexity around joins, calculations and outputs. On top of Tableau’s getting started tutorial #PreppinData has been a great way to get into Tableau Prep. I’ve invested about 12-15 hours of time and feel like I’ve got a good initial grasp of the product.
The challenge walk through provided less info on the “how”, which in some ways was quite nice as I felt more license to solve the problem my way. On the other hand I wonder if I should have made my flow less complex instead of aiming for one data set that could then be filtered down to the different outputs.