topic Re: Rankx why we have to add Calculate in the expression part? in DAX Commands and Tips

Rankx why we have to add Calculate in the expression part?

Anonymous — Sun, 29 Nov 2020 09:02:40 GMT

Hello,

I have tried the RankX function in a measure (and not in a column) but i am not sure to understand, what happened :

I mean when i don't add the Calculate function, The rank function stay to 1

RankMeasureFail2 = RANKX(ALL(Table1),SUM(Table1[Price]))

But this measure works : RankxMeasure = RANKX(ALL(Table1),CALCULATE(SUM(Table1[Price])))

A screen about my data :

Re: Rankx why we have to add Calculate in the expression part?

CNENFRNL — Sun, 29 Nov 2020 09:35:40 GMT

Hi, Anonymous , it's all about some fundamental concepts in DAX, namely evaluation context and context transition. You might want to refer to the articles I linked or google them yourself.

As to RANKX ( <Table>, <Expression> [, <Value>] [, <Order>] [, <Ties>] ), <Table> is iterator, providing row context to <Expression>. One of the most remarkable features of CALCULATE()/CALCULATETABLE() functions is context transition, the row context is transited to filter context for the calculation of expression parameter, i.e. SUM(Table1[Price]) here.

Re: Rankx why we have to add Calculate in the expression part?

wdx223_Daniel — Mon, 30 Nov 2020 02:01:17 GMT

Anonymous RANKX function creates a row context, the second parameter works on the context. if you just use SUM(), this works on current filter context, ie sum of all the price, then all the row in the same position. if add a CALCULATE function, then it transform current row context into filter context, then the sum is only of the rows filtered by this transformed context, ie sum of rows which is identical with current row.

Re: Rankx why we have to add Calculate in the expression part?

amitchandak — Mon, 30 Nov 2020 02:25:25 GMT

Anonymous , In Rankx and X function, you need to add calculate to make sure calculation get evaluated properly

Refer, it has been explained here
https://radacad.com/how-to-use-rankx-in-dax-part-2-of-3-calculated-measures
https://radacad.com/how-to-use-rankx-in-dax-part-1-of-3-calculated-columns