Count Rows in a column based on another column's distinct value

[gregtm]

I want to total the Buyers in column B based on the PO in column A.  Example  1 PO = 3 buyers (Total column)  I have tried a couple of measures Distinctcount and Count but can't seem to get it.

PO	Buyer	Total
1001	B	3
1001	C
1001	D
1002	A	4
1002	B
1002	C
1002	D
1003	B	1
1004	A	1
1005	A	2
1005	B
1007	A	3
1007	B
1007	C
1008	B	1
1009	B	2
1009	D
1010	A	3
1010	B
1010	C
1011	B	2
1011	D
1012	B	1
1013	A	3
1013	B
1013	C
1020	A	3
1020	B
1020	C
1022	A	3
1022	B
1022	C

[CoreyP · Accepted solution]

A measure like this should work:

Buyer Count per PO = CALCULATE( DISTINCTCOUNT( [Buyer] ) , ALLSELECTED( {Buyer] ) )

The reason for writing the measure this way is in your above example, you want the total number of buyers per PO within a table containing both PO and Buyer, so you need to remove the row context of Buyer from the calculation. This is what the ALLSELECTED here is doing.

[gregtm]

Thank you very much.  That works perfectly.