Data saturday # 0001 - The hidden treasure inside Power BI
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The document summarizes a Power BI session that discusses the power of the M query language. It begins with an overview of how Power Query improves upon simply accessing data. The presenter argues that M is even more powerful, allowing for complex transformations and error handling. The session then provides best practices for writing clean M code through techniques like commenting and keeping formulas visible. Next, it explores how M can be used to mash up multiple data sources. Examples show how M handles lists, records, tables and functions. Finally, a challenging real-world scenario is presented where M is used to transform complicated XML data into a clean table.
Data saturday # 0001 - The hidden treasure inside Power BI
- 1. #datasatpn February 27th, 2021 Data Saturday #1 The Hidden Treasure inside Power BI Lorenzo Vercellati
- 2. Lorenzo Vercellati BI & Power BI Architect @ 20 years burning on “Data Realm” My little contribution to the community
- 3. Session Agenda •Data is Good, PowerQuery is Better, M is Best •PowerQuery & M Best Practices •M is for MashUp •M ission (Im)possible
- 5. Data is Good Being able to access data sources of many different types is good Good data are rarities
- 6. PowerQuery is Better PowerQuery User Interface is •Office like •Easy-to-use •Powerful Make your data better
- 7. M is Best PowerQuery covers only 40% of M power M can simplify step sequence M makes possible really complex transformations With M you can manage errors
- 8. #GlobalPowerPlatformBootcamp PowerQuery & M Best Practices
- 9. Nomen - Omen
- 10. No Space, please! let Source = ……., #”Removed Non-Key Columns” = Table.SelectColumns(Source,{… let Source = ……., Removed_NonKey_Columns = Table.SelectColumns(Source,{…
- 12. Formula Bar Always on Train yourself to understand the code behind the User Interface Verify what you are really doing
- 13. #GlobalPowerPlatformBootcamp M is for MashUp
- 14. M is a functional Language Between let and in One step, One function (at least) StepName = Function(PreviousStepName, Parameters)
- 15. M is case sensitive Keep in mind! Text <> text DAX is case insensitive COD1 <> cod1 for M COD1 = cod1 for DAX
- 18. Lists {“Pippo”, “Pluto”, “Paperino”} {1..10} {{"Squadra.1", "Squadra"}, {"Squadra.2", "Schema"}}
- 19. Records
- 22. Scenario • Web page source Code • Over 3000 rows of complicated XML • Data of the same match in different tables • It’s mandatory to have Team Name as column not as general header • We need to intercept and interpretate also icons
- 23. Scenario
- 24. Scenario
- 25. Time to jump into the Demo
- 27. Reference • Chris Webb's BI Blog Chris Webb's BI Blog (crossjoin.co.uk) • The Excelguru Blog - More geeky stuff from the author of www.excelguru.ca...The Excelguru Blog | More geeky stuff from the author of www.excelguru.ca…
- 29. Thank You For Attending [email protected] @supergimi LorenzoVercellati