How to SUM the rows in column X which are selected by a DISTINCT on column Y?

[Anonymous]

I have been stuck with this issue for a while now, I want to sum the Y column, but only on DISTINCT values of Column X. If I would filter in the report on tables(Table1 & Table2), I want the measure to calculate on the table that is selected.

I have tried the following statement, but it returns an error:

Z = DIVIDE(SUMX('myTable'[Y]);DISTINCT(myTable[Table])))

Error: 

A single value for column 'gewicht' in table '_dataerror' cannot be determined. 
This can happen when a measure formula refers to a column that contains many values without specifying 
an aggregation such as min, max, count, or sum to get a single result.

Table structure myTable:

Table           X                    Y
Table1          supplier             2
Table1          customer             1
Table1          supplier             2
Table2          project              3
Table2          project              3
Table1          customer             1

The output that I am looking for here is a measure that does the following and returns one value:

If I would select Table 1:

3*2 + 2*1 / (2+1)

If I would select Table 2:

2*3 / 3

How can I get the values of column Y with using a distinct on column X ?

[v-chuncz-msft · Accepted solution]

@Anonymous ,

You may try the measure below.

Measure =
SUMX ( VALUES ( myTable[X] ), CALCULATE ( MAX ( myTable[Y] ) ) )