Option Explicit
Sub RemoveColumns()
Dim cell As Excel.Range
Dim columnsToKeep As Variant
columnsToKeep = Array("PRODUCT_ID", "PRODUCT", "CUSTOMER_ID", "DATE")
Set cell = Worksheets("Tabelle1").Range("A1")
Do Until cell.Value = ""
If IsError(Application.Match(cell.Value, columnsToKeep, 0)) Then
Set cell = cell.Offset(0, 1)
Call cell.Offset(0, -1).EntireColumn.Delete
Else
Set cell = cell.Offset(0, 1)
End If
Loop
End Sub