Populate a new column with data from conditional row

[Green_G]

Hi,

I am new to Power BI report building and I'm hoping you can help - I'm sure there is a simple solution but I don't know what it is!

I have a table like the one below and want to create an additional column called "ORIGINAL SOURCE" that shows the value in the SOURCE column for EVENT NO 1 in every row for the relevant REF VALUE.

REF	EVENT_NO	SOURCE
001	1	A
001	2	A
001	3	B
001	4	B
001	5	D
002	1	C
002	2	D
002	3	A
002	4	B
002	5	C
002	6	D

So it will look like this:

REF	EVENT_NO	SOURCE	ORIGINAL SOURCE
001	1	A	A
001	2	A	A
001	3	B	A
001	4	B	A
001	5	D	A
002	1	C	C
002	2	D	C
002	3	A	C
002	4	B	C
002	5	C	C
002	6	D	C

I would appreciate anyone's advice on the best way to achieve this.

Many Thanks,

[smpa01 · Accepted solution]

@Green_G  you can write a measure like this

Measure2 = 
//what is the min event # by REF
VAR one =
    CALCULATE (
        MIN ( 'Table 1'[EVENT_NO] ),
        ALL ( 'Table 1' ),
        VALUES ( 'Table 1'[REF] )
    ) // what is the source when event = one by ref
VAR two =
    CALCULATE (
        MIN ( 'Table 1'[SOURCE] ),
        FILTER (
            ALL ( 'Table 1' ),
            'Table 1'[EVENT_NO] = one
                && 'Table 1'[REF] = MAX ( 'Table 1'[REF] )
        )
    )
RETURN
    two