Performing calculation only on last 3 values in column (DAX)

[Anonymous]

Hi all,
I hope someone can help me by suggesting DAX formula for this scenario. I have this column in Excel that I need to replicate in PowerBI

Any idea how this can be achieved?Thanks in advance for your help.

[amitchandak · Accepted solution]

@Anonymous , You need some kind of index on the tabled, based that we can get max index and do the operation

Power Query- Index Column: https://youtu.be/NS4esnCDqVw

But across to means you have sum all column (DAX example)

new column =

var _max(Table[Index])

Var _secondLast = sumc(filter(Table, Table[index] = _max -1 ), [Col1]+[Col2]+[col3])

Var _Last = sumc(filter(Table, Table[index] = _max ), [col3])

Var _ThirdLast = sumc(filter(Table, Table[index] = _max ), [col3])

return

_ThirdLast + _secondLast  -_Last 

[Anonymous]

I was able to figure it out using your formula,thank you a lot!🤗