Remove columns contain null on the end

Column1 Column2 Column3 Column4 Column2 Column4
A D I M D M
B E J N E N
C F K O F O
G L P G P
H R H R


Code:
let
    Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content],
    TSC = Table.SelectColumns(Source, Table.SelectRows(Record.ToTable(Table.Last(Source)), each [Value] <> null)[Name])
in
    TSC