Equal bins in DAX equivalent of NTILE function - powerbi

Question

I would like to imitate NTILE function of SQL in DAX. For a given number of bins, I would like a measure which returns the bin number for any value in a column. The bins should contain more or less equal number of observations.
So the parameters are:
number of bins
test value
table column
Here is something similar in Excel:
= MAX( ROUNDUP( PERCENTRANK($A$1:$A$8, A1) *4, 0),1)

Answer 1

In DAX, you can use the PERCENTILE.INC as the base for such a calculation.
Bucket =
VAR N = 4
VAR Percentiles =
ADDCOLUMNS (
GENERATESERIES ( 1, N ),
"Percentile", PERCENTILE.INC ( Table1[Col1], [Value] / N )
)
RETURN
MINX ( FILTER ( Percentiles, Table1[Col1] <= [Percentile] ), [Value] )
For your data, the Percentiles table variable looks like this:
Value Percentile
1 24.8
2 66.5
3 81.8
4 85.0
Then for each row in your original table, you take the minimum value from the calculated table where that Percentile column is less than or equal to the original table column Col1 in that row.
Note that the above is for a calculated column. For a measure, you'd need to specify an aggregation for Table1[Col1] in the last line (e.g. MAX(Table1[Col1])).