Dynamic Unpivot in PowerQuery

[WV]

Hi,

I have a table populating from SharePoint list. In this table I have a set columns in a tabular format. I have added a screen shot for reference. I am trying to unpivot the data so that there is one Date column, one Capital column, one Notes column, and one Expense column. Right now there are 26 of each.  They also keep adding new SP columns so I would like it to be dynamic so it always automatically captures the new data. 

Here is where I have started: 

let
Source = SharePoint.Tables("http://inside/private/CAM/", [ApiVersion = 15]),
#"0cb52d41-3597-476f-b8eb-e2020540e973" = Source{[Id="0cb52d41-3597-476f-b8eb-e2020540e973"]}[Items],
#"Unpivoted Columns" = Table.Unpivot(Source, List.Select(Table.ColumnNames(Source), each (Text.StartsWith("SP") and Text.EndsWith("Date"))), "Attribute", "Value")
in
#"Unpivoted Columns"

BUT I am getting this error: 

Expression.Error: 1 arguments were passed to a function which expects between 2 and 3.
Details:
Pattern=
Arguments=[List]

I need to make a condtional unpivot saying if the column starts with SP and Ends with Date - then put that into one date column, then do the same for Expense, Notes, and Capital. 

Thank you for any and all support. 

[lbendlin]

When you unpivot you need to specify at least one fixed point - a column that does not change.

[WV]

Where in the syntax would I specify that? 

Source = SharePoint.Tables("http://inside/private/CAM/", [ApiVersion = 15]),
#"0cb52d41-3597-476f-b8eb-e2020540e973" = Source{[Id="0cb52d41-3597-476f-b8eb-e2020540e973"]}[Items],
#"Unpivoted Columns" = Table.Unpivot(Source, List.Select(Table.ColumnNames(Source), each (Text.StartsWith("SP") and Text.EndsWith("Date"))), "Attribute", "Value")
in
#"Unpivoted Columns"

Thanks,

Wendy

[lbendlin]

Please provide a sample of your SP list and indicate the expected result.