Custom column to count number of unique occurrences of a key value for a PK column

[Anonymous]

In PowerQuery I want to add a custom column that provides total number of unique occurences of a key value for a primary key column 

For example,  new custom column(Count) should be created based on total number of unique occurences of ID for a certain Key
Below screen shot is what I'm trying to create

[sevenhills · Accepted solution]

Try this:

ID Count per Key = 
CALCULATE(
	DISTINCTCOUNT('TableKeyCountMeasure'[ID]),
	Allexcept('TableKeyCountMeasure', 'TableKeyCountMeasure'[Key])
)
 

[Anonymous]

AWESOME !!

[Anonymous]

Thanks for the help, this works as expected