Measure to find first & second instance

govi See my article on Mean Time Between Failure (MTBF) which uses EARLIER: http://community.powerbi.com/t5/Community-Blog/Mean-Time-Between-Failure-MTBF-and-Power-BI/ba-p/339586.
The basic pattern is:
Column = 
  VAR __Current = [Value]
  VAR __PreviousDate = MAXX(FILTER('Table','Table'[Date] < EARLIER('Table'[Date])),[Date])

  VAR __Previous = MAXX(FILTER('Table',[Date]=__PreviousDate),[Value])
RETURN
  __Current - __Previous

In your case you will want to use MINX. If you can provide sample data as text and expected output can be more specific.

govi , Create this new column Rank and filter for 1,2

rankx(filter(Table, [userId] = earlier([userId])), [DataTime],,asc,dense)

For Rank Refer these links

https://radacad.com/how-to-use-rankx-in-dax-part-1-of-3-calculated-columns
https://radacad.com/how-to-use-rankx-in-dax-part-2-of-3-calculated-measures

Hi VGRG and amitchandak ,

Thanks for you help!

This is an example of the data (as picture and as csv, I cannot attach a txt or xls file):

DateTime;userId;question;answer;
27-11-20 10:41;161694;Are you male or female?;Male;
27-11-20 10:41;161694;What is your age?;39;
27-11-20 10:41;161694;What's your height?;190;
27-11-20 10:41;161694;What's your weight?;120;first
27-11-20 20:06;161696;Are you male or female?;Male;
27-11-20 20:06;161696;What is your age?;51;
27-11-20 20:06;161696;What's your height?;183;
27-11-20 20:06;161696;What's your weight?;92;
01-12-20 20:11;161696;What's your weight?;92;
02-12-20 19:51;161694;What's your weight?;115;second
04-12-20 19:27;163513;Are you male or female?;Male;
04-12-20 19:27;163513;What is your age?;47;
04-12-20 19:27;163513;What's your height?;170;
04-12-20 19:27;163513;What's your weight?;88;
04-12-20 19:34;163513;What's your weight?;92;
07-12-20 20:12;161696;What's your weight?;94;
08-12-20 19:57;161694;What's your weight?;117;third
11-12-20 20:21;163513;What's your weight?;87;
etc;etc;etc;etc;

I need a measure to isolate the first and an measure to isolate the second weight(answer) per user.

When I have them isolated I can use them for a calculation I need to perform.

Can you help?

Thanks a lot!

govi

Hi govi ,

According to my understanding, you want to filter the first/second record based on each userId ,right?

You could use RANKX() function like this to rank by some userId and DateTime:

rank =
RANKX (
    FILTER (
        ALL ( 'Table' ),
        'Table'[userId] = MAX ( 'Table'[userId] )
            && 'Table'[question] = MAX ( 'Table'[question] )
    ),
    CALCULATE ( MAX ( ( 'Table'[DateTime] ) ) ),
    ,
    ASC
)

Then for example, if you want to sum all the weights ranked first/second, use SUMX() function:

Second =
SUMX (
    FILTER ( 'Table', [rank] = 2 && 'Table'[question] = "What's your weight?" ),
    VALUE ( 'Table'[answer] )
)

Or apply 'Table'[question] = "What's your weight?" to page-level filter to simplify measure like this:

First =
SUMX ( FILTER ( 'Table', [rank] = 1 ), VALUE ( 'Table'[answer] ) )

Please take a look at the pbix file here.

Best Regards,
Eyelyn Qin

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

HotChilli Anonymous amitchandak Greg_Deckler 

Thank you all for your help! During the holidays I closed my laptop for 2 weeks.

I use HotChilli 's solution

Thanks again and happy new year!

govi