DAX index Function how to use?

[Dicken]

Hi, I have not used index in dax pbi, but thouhgt I'd have a look, so created a date table ; 

dDate = 
 ADDCOLUMNS( 
 CALENDAR( DATE( 2020,1,1), DATE( 2025,12,31) ) , 
 "Year", YEAR([Date]), 
 "Month", FORMAT([Date],"MMM") , 
 "ms", MONTH([Date]), 
  "FiscalQ",  CEILING( MONTH( EDATE([Date],-3)),3) /3
 )

and then decided to use index to bring back the top row,  so in excel Index( Table, 1, 0 )  , 

Table = INDEX(1 , dDate, ORDERBY(dDate[Date]) )

but i get a message saying it may have duplicate rows, well it's a calendar so I don't think so,   
Richard. 

[amitchandak · Accepted solution]

@Dicken , I created a table with the same code, and it worked

In case of measure use

Maxx( INDEX(1 , dDate, ORDERBY(dDate[Date]) ), [Date])

Power BI Index function: Top/Bottom Performer by name and value- https://youtu.be/HPhzzCwe10U

[Dicken]

no, 

 CALENDAR(DATE(2020,1,1), DATE(2020,12,31)  ) ,
Then new table 

  Table 2 = DISTINCT(WINDOW(1,ABS,1,ABS ,'Table') ) 
Erorr message 
  WINDOW's Relation parameter may have duplicate rows. This is not allowed. 

But it will acceept 

Table = WINDOW(1,ABS,1,ABS,
 CALENDAR(DATE(2020,1,1), DATE(2020,12,31)  ) ) 

Richard. 

[amitchandak · Accepted solution]

@Dicken , I created a table with the same code, and it worked

In case of measure use

Maxx( INDEX(1 , dDate, ORDERBY(dDate[Date]) ), [Date])

Power BI Index function: Top/Bottom Performer by name and value- https://youtu.be/HPhzzCwe10U

[Dicken]

Sorry, just to add did this in power pivot Dax studo, but this is what I would expect index to return, 
a one row  ( top ) table; 

EVALUATE 
 FILTER( 'Calendar', 
  'Calendar'[Date] = DATE( 2020,1,1) 
  )

Richard. 

[Dicken]

So does it return a table, as that's what I was using; 

New Table,  

Table = INDEX(1, dDate, ORDERBY(dDate[Date],ASC) 

out of interest I get the same message for window.   

Table 2 = WINDOW( 1,ABS,1,ABS,dDate )  again I get duplicate error message, 

so still none the wiser as to how it works,   
i thought I'd try a simpler date table ; 
dDate = ADDCOLUMNS(

 CALENDAR( DATE( 2020,1,1), DATE(2020,12,31) ),

 "Year", YEAR([Date]),

 "Month", FORMAT([Date],"MMM")

) 

and put this into studio,  but get message,  an item with the saem key has already been added? 
Don't have these problems in power pivot. 

Richard 

[Daniel29195 · Accepted solution]

@Dicken Try this : 

 use distinct around  the table you are using in window functions 

let me know if this works 

[Dicken]

Thanks, 

RD