Full Anti Join (M not DAX)

smpa01 I've tried this way... 

let
    Source = Table.NestedJoin(Test296FullAntiJoinT1,{"Data"},Test296FullAntiJoinT2,{"Data"},"Test296FullAntiJoinT2",JoinKind.FullOuter),
    #"Expanded Test296FullAntiJoinT2" = Table.ExpandTableColumn(Source, "Test296FullAntiJoinT2", {"Data", "Value"}, {"Test296FullAntiJoinT2.Data", "Test296FullAntiJoinT2.Value"}),
    #"Added Custom" = Table.AddColumn(#"Expanded Test296FullAntiJoinT2", "DataNew", each if [Data] = null then [Test296FullAntiJoinT2.Data] else if [Test296FullAntiJoinT2.Data] = null then [Data] else null),
    #"Added Conditional Column" = Table.AddColumn(#"Added Custom", "ValueNew", each if [Value] = null then [Test296FullAntiJoinT2.Value] else if [Test296FullAntiJoinT2.Value] = null then [Value] else null),
    #"Filtered Rows" = Table.SelectRows(#"Added Conditional Column", each ([DataNew] <> null)),
    #"Removed Columns" = Table.RemoveColumns(#"Filtered Rows",{"Data", "Value", "Test296FullAntiJoinT2.Data", "Test296FullAntiJoinT2.Value"})
in
    #"Removed Columns"

Maybe something like this could work?

• Append the two tables
• Groupby Data, and aggregating by Count Rows as well as all rows
• Filter the count to equal 1
• Expand the All Rows 
• Remove misc columns and set data types

let
    Source = Table.Combine({Table1, Table2}),
    #"Grouped Rows" = Table.Group(Source, {"Data"}, {{"Count", each Table.RowCount(_), type number}, {"Data.1", each _, type table}}),
    #"Filtered Rows" = Table.SelectRows(#"Grouped Rows", each ([Count] = 1)),
    #"Expanded Data.1" = Table.ExpandTableColumn(#"Filtered Rows", "Data.1", {"Value"}, {"Value"}),
    #"Removed Columns" = Table.RemoveColumns(#"Expanded Data.1",{"Count"}),
    #"Changed Type" = Table.TransformColumnTypes(#"Removed Columns",{{"Value", Int64.Type}})
in
    #"Changed Type"