Combine different columns from excels files!

[philongxpct]

             I have a nested tables (3 Columns: Name - Excel file's name; Combined - What columns to keep; D - workbook table). Ends users will type what columns to keep (mess columns per file :<) that my case. So, I want to select these columns dynamicly way.

             I try to play around with my data via this approach: https://bondarenkoivan.wordpress.com/2016/01/25/rename-columns-of-nested-tables-in-power-query/ but hard to rename columns cos so many dulicate columns.

             Now i trying to transforms "Table" columns before expand it base on same next rows content "Combine": = Table.TransformColumns(Custom1, {{"D", each Table.SelectColumns("D",[Combined],[Combine])}})

            So, yeah that error i face off. Anyone can help pls.

P/s: Sorry cos my english :<<.

[philongxpct]

Update:

                Just play around with https://bondarenkoivan.wordpress.com/2016/12/12/transform-column-using-custom-function-in-power-quer...

                My code here:

Custom2 = Table.FromRecords(Table.TransformRows(Custom1),
                      (ref)=> Record.TransformFields(ref,
                                    {"D", each Table.SelectColumns(ref[D],ref[Combine],ref[Combine])}))

                And new error:

Expression.Error: 1 arguments were passed to a function which expects 2.
Details:
Pattern=
Arguments=List

                Still play around, any help is appricicated. Thanks

Happy querying guys ^^!

[MarcelBeug · Accepted solution]

My suggestion would be to add a Custom Column with formula:

= Table.SelectColumns([D],Text.Split([Combined],","))

Next you can remove column D.