基于两个过滤器的单个表上的单个非重复计数度量-每个过滤器值位于单个表的不同行上

Question

I'm trying to demo some more complex DAX / powerpivot concepts to people on my team. I came up with an example to walk them through, but I think might actually be impossible.

Happy to change the example to something else, but this has really piqued my interest. Does anyone know how to do it?

Here's some example data, single table, nothing fancy...

    Child ID | Type      | Parent ID
    1        | A         | 1
    1        | A         | 2
    1        | B         | 3
    1        | C         | 4
    2        | B         | 436
    2        | B         | 983
    2        | A         | 24
    2        | A         | 444
    3        | A         | 67
    3        | A         | 67
    3        | B         | 4
    3        | B         | 3

What I'd like to do is - per Child ID, Distinct Count Parent IDs of Type A which have a Parent ID of 4 attributed to it somewhere... in a single measure...

So the result in a pivot would be....

    Child ID | DCnt_PiD
    1        | 2
    2        | 0
    3        | 1

I have played around with this in a DAX query editor, trying crossjoins, generates mixed with addcolumns etc. but they didn't work (cannot join a table with the same column id etc.)...

The measure would then relate over to another table via a bridge table, so can't use a pivot I'm afraid...

Anyone got any ideas?

Cheers

Answer 1

Cracked it in a DAX Query, now time to turn it into a measure!

EVALUATE
 (
    SUMMARIZE (
        FILTER (
            SUMMARIZE (
                table,
                table[Child_ID],
                table[Type],
                table[Parent_ID]
            ),
            table[Type] <> "B"
                && table[Type] <> "C"
                && CALCULATE (
                    COUNTROWS ( table ),
                    ALLEXCEPT ( table, table[Parent_ID], table[Child_ID] ),
                    table[Parent_ID] = 4
                )
                    > 0
        ),
        table[Child_ID],
        "DCnt_Pid", DISTINCTCOUNT ( table[Parent_ID] )
    )
)
ORDER BY [Child_ID]