Creating Dynamic Column Selection

[Mitchell_Collier]

I am trying to get all of the columns from my merged query to populate dynamically. Item Quantity (2) is a table with rows of items and quantity by month in columns. Can anyone figure out this error?

= Table.ExpandTableColumn(#"Merged Queries2", "Item_Quantity (2)", List.Union(List.Transform(Month[Month]), each Table.ColumnNames(_)))

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

• 
  
  
  
  Month Query (with Month as column name)
  
  Month
  February
  March
  April