Full outer join with three tables

Hi, mr_oli 

Based on your description, I created data to reproduce your scenario. The pbix file is attached in the end. 

You may try creating a calculated table as below.

Table = 
ADDCOLUMNS(
    DISTINCT(
        UNION(
            DISTINCT(Table1[Column1]),
            DISTINCT(Table2[Column1]),
            DISTINCT(Table3[Column1])
        )
    ),
    "Column2",
    MAXX(
        FILTER(
            Table1,
            Table1[Column1]=EARLIER(Table1[Column1])
        ),
        [Column2]
    ),
    "Column3",
    MAXX(
        FILTER(
            Table2,
            Table2[Column1]=EARLIER(Table1[Column1])
        ),
        [Column3]
    ),
    "Column4",
    MAXX(
        FILTER(
            Table3,
            Table3[Column1]=EARLIER(Table1[Column1])
        ),
        [Column4]
    )
)

Result:

Best Regards

Allan

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