# Sigma Computing Explained to a Tableau User | A conversation with Katrina Menne

> This is content from just-tim, the data-and-analytics channel by Tim Ngwena (formerly 'Tableau Tim'). Tim has 12+ years of hands-on BI experience and covers Tableau most of all, plus Power BI, Looker, Hex, SQL and data modelling, the analytics industry, and the craft of doing the job — always tool-agnostic and honest about the trade-offs.

- **Author:** Tim Ngwena (just-tim, https://just-tim.com/about)
- **Published:** 2024-08-13
- **Format:** Video · 106 min watch · transcript available
- **Topics:** Tool strategy, Data visualisation, Industry trends
- **Tools:** Sigma (formulas, pivot tables, visualisations, workbooks); Tableau (lod expressions, prep)
- **Canonical:** https://just-tim.com/posts/sigma-computing-explained-to-a-tableau-user-a-conversation-with-katrina-menne
- **Watch:** https://www.youtube.com/watch?v=IxfnZbrdjdE

I sat down with my Aimpoint Digital colleague Katrina Menne, who wrote the book on Sigma, to explain Sigma Computing to the Tableau community. We talk through her journey from Excel to Tableau to Sigma, the state of the analytics market, and she gives a live walkthrough of how Sigma's spreadsheet interface handles calculations, aggregations and visualisations.

## Key takeaways

- Sigma can be thought of as Tableau Desktop plus Tableau Prep combined with an Excel-style interface, putting a spreadsheet layer on top of SQL against cloud databases.
- Where Tableau builds top-down (starting with an aggregation like SUM(Sales) and using LODs to drill down), Sigma builds bottom-up from the row level using group-by statements to work up.
- Sigma's what-you-see-is-what-you-get table makes the row-level versus aggregate distinction obvious, removing a concept many new analysts struggle with in Tableau.
- When learning a new BI tool, drop your old tool's preconceptions and start with familiar data (e.g. loading Superstore into Sigma) rather than trying to recreate the old workflow.
- The valuable skills are data skills, not tool skills; the practitioner of the future is multi-tool, so learn fundamentals like part-to-whole and time-series analysis that transfer across platforms.

## Chapters

- 0:00 Why compare Sigma to Tableau now
- 1:44 Meet Katrina Menne
- 5:49 Learning Tableau the hard way
- 10:24 From the SALT stack to Sigma
- 16:04 The changing analytics landscape and AI
- 20:55 What is Sigma?
- 24:57 Sigma on modern cloud databases
- 35:28 Live demo: building calculations
- 45:12 Adding visualisations and lineage
- 48:42 Dropping preconceptions when learning a new tool
- 51:29 The multi-tool future and data skills
- 53:40 A finished dashboard example

Watch the full video, read the transcript and use chapter deep-links on the page: https://just-tim.com/posts/sigma-computing-explained-to-a-tableau-user-a-conversation-with-katrina-menne

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just-tim — Data and analytics, with a point of view. · https://www.youtube.com/channel/UC7HYxRWmaNlJux-X7rNLZyw · https://twitter.com/TableauTim · https://www.linkedin.com/in/timngwena