Context Transition - The Whiteboard #03

A context transition in DAX transforms a row context into an equivalent filter context: a picture is worth a thousand words!


#thewhiteboard

[richardmartin]

Please keep doing these type of videos. Very useful for people like me.

[sarthaks]

The most important and complex concept in DAX.. This is really helpful

[mwaltercpa]

Visually seeing each row move into the filter context to evaluate (under filter context) really helps solidify the role of row context within a filter context evaluation. Thanks Marco!

[bradj]

Thanks for explaining with visuals. It helped me understand a lot easier :)

[MilhouseBS]

7:38 Good point on internal optimization on iteration. Didn't know that.

[lmblancoancos]

Thank you so much Marco. This video together your book and articles are the best tool to learn about this concept😀

[TheBaozi]

This is the best explanation of context transition! Thank you so much! I can't wait to see others episodes.😍

[Nura]

Thank you Marco! Exellent explanation!👏

[williamarthur]

Interesting as ever. I hope you do variables, I'm on that chapter and trying to understand where to put them, I've always placed at very start, but had a situation where I had to declare within Calculate and want to understand 'Why?'. Ottimo libro, ottimo sito, ottimi video. Don't ever drop the catch phrase.

[simon]

Thanks Marco for the video. In your example, I understand after context transition, there are 3 filters (year, brand, and max), but remember the sales amount = sumx (sales, price & qty), so the sales amount itself is a sum over many rows. But on top of that, there is a max. Is the max replacing the sum in the sales amount measure? Is the outcome of max a single row's sale amount, or a sum of the sales amount column? thanks a lot!

[liang-tsairlin]

Hello, I am wondering if you can help me using DAX to identify the customers who have the max sales in the first matrix (table) cited instead of just the numbers. By the way, great presentations for all 3 whiteboards. Thank you.

[OlsoNounas]

At 3:02 you said that the customer table is filtered. Technically, isn't this incorrect? It's the sales table which is filtered and the customer table can only iterate over a filtered version of the sales table, or am I missing something?

[holahandstrom]

I would create the 'Explicit table' that =MAXX() iterates over.
It takes less brain-compute to understand, than an Implicit (conceptual) explanation.

[mshparber]

Thanks! Can you please show an example where you use two columns inside a MAXX, two columns from different tables, lets say Product and Country. Here DISTINCT or VALUES will not work. What is recommended to use?

[MTawfik]

the most confusing video I have ever watched :)

[yyymmmddd]

Isn't this explanation simpler: The MAXX function only sees Contoso 2019 rows of the expanded table and calculates max amount for the relevant cell in the visual ?

[Spirovsk]

whats the difference between using distinct versus values ?

[QuLaZz]

Maybe it would be better to use Dax studio, to show real data for every step of the calculation.
So we can see the Distinct Country, Sales Amount for Contoso and 2019, and then to see the Max value.

[sandeepbarge]

How does it understand that it should take max of sales only for those customers that have sales for given brand and product? Because filters on date and product tables are not propagated to customers table. How and when does it filter customers that have sales only for given brand and date? Sorry if I missed something. Please can you clarify?

[coollehavre]

it doesnt work in my sample database : my sales amount are : Total Ventes = SUMX( '💲Ventes', '💲Ventes'[Prix Vente]*'💲Ventes'[Qté] ) and my measure to have the maxx : Max Ventes Commerciaux =
MAXX(
VALUES('💲Ventes'[Commercial]),
[Total Ventes])
but the result is the same than the SUM, not the MAX by month ?