CALCULATE behaviour when using in a new column

[Arklur]

I have a very simple source data to demonstrate my problem I run into:

I can easily calculate the total "Amount" of the "Child" table for the "Parent" table using a simply DAX:

SumTotalValue = CALCULATE(SUM(Child[Amount]))

But if I try to add a new filter for CALCULATE, looks like it drops the filter context and only use the one I provided:

SumBefore2017 = CALCULATE(SUM(Child[Amount]); FILTER(Child;Child[Year] < 2017))

+1: I realized I (likely) should use these DAX expressions for such usage (I think it provides a better performance, though haven't checked it yet):

SumTotalValue = SUMX(RELATEDTABLE(Child);Child[Amount])

SumBefore2017 = SUMX(FILTER(RELATEDTABLE(Child);Child[Year] < 2017);Child[Amount])

,but still curious about this behaviour.

[OwenAuger · Accepted solution]

Hi @Arklur

Probably the simplest way to write your 2nd calculated column is:

SumBefore2017 =
CALCULATE ( SUM ( Child[Amount] ); Child[Year] < 2017 )

The reason your original version lost the filter context obtained from the row of Parent (through context transition) was that the FILTER(Child...) argument over-rode it.

1. FILTER(Child...) is evaluated in the original context (outside CALCULATE) where Child is unfiltered.
2. On top of that, Child when used as a filter argument within CALCULATE is treated as the expanded table which includes all columns of Parent, so including it as a filter argument over-rides the filter context obtained from the "current row" of Parent.
3. The suggested calculated column above adds a filter only on Child[Year], so the other filters on columns of the Parent table are retained.

Here are a couple of good articles that cover these points in more depth:

https://www.sqlbi.com/articles/context-transition-and-filters-in-calculate/

https://mdxdax.blogspot.com/2011/03/logic-behind-magic-of-dax-cross-table.html

Regards,

Owen

[v-shex-msft]

Hi @Arklur,

After checking your formula, I found you forget to add condition to check current parentID, you can try to use below measure(calculated column) to achieve your requirement.

SumBefore2017 =
CALCULATE (
    SUM ( Child[Amount] );
    FILTER (
        ALL ( Child );
        Child[ParentId] = EARLIER ( Parent[ParentId] )
            && Child[Year] < 2017
    )
)

Regards,

Xiaoxin Sheng

[Stachu]

I suggest creating measures instead of columns - with the same syntax, they will propagate filter context properly
as a measure SumBefore2017 can be just

SumBefore2017 = CALCULATE(SUM(Child[Amount]); Child[Year] < 2017)

[Arklur]

Thanks for the idea, though it doesn't really answer my question / I've already knew the downsides of creating calculated columns instead of creating them as a measure.